Eric throws a biased coin 10 times. He gets 3 tails. Sue throw the same coin 50 times. She gets 20 tails. Aadi is going to throw the coin once.
1. Which one of the following statements is, cotlrrect about the probability of Aadi getting Tails?
A. Sue's estimate is best because she throws it 50 times.
B. Sue's estimate is best because she gets more Tails.
C. Sue's estimate is best because she throws it more times than Eric

2. Use Eric's and Sue's results to work out an estimate for the probability that Aadi will get Tails. Write out your fraction in the form a/b


P. S WILL MARKS AS BRAINIEST AND THANK IF YOU ANSWER DECENTLY

Eric Throws A Biased Coin 10 Times. He Gets 3 Tails. Sue Throw The Same Coin 50 Times. She Gets 20 Tails.

Answers

Answer 1

Answer:

(1) The correct option is (A).

(2) The probability that Aadi will get Tails is [tex]\frac{2}{5}[/tex].

Step-by-step explanation:

It is provided that:

Eric throws a biased coin 10 times. He gets 3 tails.Sue throw the same coin 50 times. She gets 20 tails.

The probability of tail in both cases is:

[tex]P(\text{Tail})=\frac{3}{10}[/tex] [tex]P(\text{Tail})=\frac{20}{50}=\frac{2}{5}[/tex]

(1)

According to the Central limit theorem, if from an unknown population large samples of sizes n > 30, are selected and the sample proportion for each sample is computed then the sampling distribution of sample proportion follows a Normal distribution.

In this case we need to compute the proportion of tails.

Then according to the Central limit theorem, Sue's estimate is best because she throws it n = 50 > 30 times.

Thus, the correct option is (A).

(2)

As explained in the first part that Sue's estimate is best for getting a tail, the probability that Aadi will get Tails when he tosses the coin once is:

[tex]P(\text{Tail})=\frac{20}{50}=\frac{2}{5}[/tex]

Thus, the probability that Aadi will get Tails is [tex]\frac{2}{5}[/tex].

Answer 2

Answer:

Answer is C

Step-by-step explanation:

The more you throw the coin the more reliable the test becomes, therefore C is most definitely the correct answer :)


Related Questions

Solve this inequality.
7x + 2 > 30
A.x 224
B.x > 196
C.x 4
D.x > 3​

Answers

Answer:

x > 4

Step-by-step explanation:

7x + 2 > 30

Subtract 2 from each side

7x + 2-2 > 30-2

7x > 28

Divide each side by 7

7x/7 > 28/7

x > 4

Answer:

it is c

Step-by-step explanation:

John received 3 detentions in the fourth quarter. He received 4 other
detentions for 1st and 2nd quarters combined. He received 12 for the
whole school year so how many detentions did he receive in the 3rd
quarter?

Answers

Answer:

5

Step-by-step explanation:

12 - (3+4)

12 - 7

12 - 7 = 5

5

Answer:

5

Step-by-step explanation:

12 - (3 + 4)

12 - 7

12 - 7 = 5

Find the areas of the trapezoids.

Answers

Answer:

30 square units

Step-by-step explanation:

i did this problem before.

The answer is 12. Since the scaling factor is 2 you have to multiply all the squares by two. And if you find the area using a scaling factor of one you get 6

Which of the lines below is a line of symmetry?
A. Neither
B. Red
C. Yellow
D. Both

Answers

Answer:

d, both

Step-by-step explanation:

both separe two identical halves :)

Both yellow and red lines are lines of symmetry to the given figure, Option D is correct.

What is Coordinate System?

A coordinate system is a system that uses one or more numbers, or coordinates, to uniquely determine the position of the points or other geometric elements on a manifold such as Euclidean space.

A line of symmetry is the line that divides a shape or an object into two equal and symmetrical parts.

We know that the diameter of a circle is a line passing through its center. So, the diameter acts as a line of symmetry dividing the circle into two parts with equal area.

In the given figure both the lines represents symmetry as both the lines are dividing the figure to two equal parts.

Hence, both yellow and red lines are lines of symmetry to the given figure, Option D is correct.

To learn more on Coordinate system click:

https://brainly.com/question/30241634

#SPJ5

The age of father is three times the age of son. If the age of son is 15 years old, then the age of father is:
50 years
55 years
45 years
40 years

Answers

It’s 45 years old sorry,if I’m wrong.
The age of the father is 45 years

Which expression is equivalent to 3x + 6y?

Answers

Answer:

3x+6y =0

-6y

3x=-6y

x=-2y

Step-by-step explanation:

Plz Help!
Hank has cards that are 4 inches by 2 inches. A stack of these cards fits inside the box shown and uses up 8 cubic inches of volume.

L 4 in.
W 2 in.
H 2 in.

Part 1 out of 2
How tall is the stack of cards?

The stack is ___ inch(es) tall.

Answers

The stack of cards are 1 inch tall all together taking up 8 inch’s (cubed)or half of the space

What is 40% of 160?
A. 20
B. 40
C.
32
D. 64
E.
75




it's 64​

Answers

AnswerD. 64

Step-by-step explanation:

Answer:

D.) 64

Step-by-step explanation:

What reason allows the following statement to be true?
Given AB + CD = JK and CD = 5, then AB + 5 = JK​

Answers

Answer: Subtituting CD =5 in AB + CD = JK

Step-by-step explanation:

Hi, to answer this question we have to analyze the information given:

• AB + CD = JK (equation 1 )

• CD = 5 (equation 2)

So, we simply have to combine the equations.

Substituting CD =5 in equation 1:

AB + CD = JK

AB+(5) =JK

Feel free to ask for more if needed or if you did not understand something.  

HELP ASAP!

A health insurance provider had net incomes of $356 million, $460 million and -$166 million in 3 consecutive years. What was the health provider's total net income for these three years?

Answers

Step-by-step explanation:

The total income would be $650 million.

True or False?
When multiplying powers with the same base, you subtract the exponents. When dividing powers with the same base, you multiply the exponents. When raising a power to a power, you divide the exponents? EXPLAIN YOUR REASONING

Answers

Answer:

False

Step-by-step explanation:

(x^3)(x^4) = (xxx)(xxxx) = x^7 when multiplying you add the exponents

(x^5)÷(x^2) = (xxxxx)÷(xx) = xxx or x^3 because two of the x's reduce therefore when dividing you subtract the exponents

(x^2)^3 = (x^2)(x^2)(x^2) = (xx)(xx)(xx) = x^6 when raising a power to a power you multiply the exponents

multiply: (sqrt10 +2 sqrt8)(sqrt10-2 sqrt8)

Answers

Answer:

(√10 +2√8)(√10 -2√8)=

(10 -8√5 + 8√5 -32)

10+0-32

10-32

= -22

Hope this helps.

Answer:

The other person is right, A. -22

Step-by-step explanation:

Find distance of each

Answers

Answer:

4

Step-by-step explanation:

Since the y value is the same, we only have to look at the x value

-1 - -5

-1 +5

4

The distance is 4

Answer: The distance of this segment is 4 units

Step-by-step explanation:

Obviously, you could count the number of units in this graph, but for the sake of math, let’s use the distance formula, which is:

d = √([tex]x_{2}[/tex] - [tex]x_{1}[/tex])² + ([tex]y_{2}[/tex] - [tex]y_{1}[/tex])²

We know that the two endpoints of our line segment are (-1, -4) and (-5, -4). So we will use these coordinates and substitute them into the equation. The -4s will be our y coordinates, and our -1 and -5 will be our x coordinates.

d = √((-5) - (-1))² + ((-4) - (-4))²

d = √(-4)² + (0)²

d = √16 + 0

d = √16

d = 4

This furthermore proves that the distance between the two segments is 4.

Hope this helps! :)

Rod has to read a book which has p pages. He plans to read r pages each day for d days.
Write an equation for the number of pages left, b, in the book, after d days.

Answers

Answer:

Look at the attachment

The equation is an illustration of a linear function.

The equation for the number of pages left in the book is [tex]b =p- rd[/tex]

The total number of pages is:

[tex]Total = p[/tex]

The daily rate is:

[tex]Rate = r[/tex]

So, the number of pages read in d days is:

[tex]Pages = Rate \times Days[/tex]

This gives

[tex]Pages = r \times d[/tex]

Multiply

[tex]Pages = rd[/tex]

The number of pages left (b) is then calculated as:

[tex]b =Total - Pages[/tex]

So, we have:

[tex]b =p- rd[/tex]

Hence, the equation for the number of pages left in the book is [tex]b =p- rd[/tex]

Read more about linear equations at:

https://brainly.com/question/14323743

When the two crews start working together, what part of all
the garbage bins will the first garbage truck empty?
The crew of a garbage truck takes 5 hours to empty all the
bins in one neighborhood on pickup day. The city assigned
a second garbage truck to this neighborhood. During their
training, it took the crew from the second truck 8 hours to
empty all the bins.
0.6
0.5
0.7
Time
(hours)
t
Part of Bins
Emptied
Rate
(part/hour)
1
5
0.4
First Truck
500
(9
1
t
Second
Truck
1
8
8​

Answers

This question is not properly written

Complete Question

When the two crews start working together, what part of all

the garbage bins will the first garbage truck empty?

The crew of a garbage truck takes 5 hours to empty all the bins in one neighborhood on pickup day. The city assigned a second garbage truck to this neighborhood. During their training, it took the crew from the second truck 8 hours to empty all the bins.

Options

• 0.6

• 0.5

• 0.7

Answer:

0.6

Step-by-step explanation:

Let us say that the total hours worked by both trucks = t hours

Number of hours worked by first truck = 5 hours

Number of hours worked by second truck = 8 hours

Let 1 =  total number of bins.

For the 1st truck the rate at which work was carried out is

(1 ) ÷ (5 ) = 1/5

For the 1st truck the rate at which work was carried out is

( 1 ) ÷ (8 ) = 1/8

Then,

(1/5 + 1/8) × t =1

(1/5 + 1/8) × t= 1

(13/40)t = 1

t = 1÷ 13/40

t = 1× 40/13

t = 40/13 hours.

Hence, the total hours worked by both trucks = 40/13 hours

the part of all

the garbage bins that the first garbage truck will empty is calculated as:

1/5 × 40/13 hr

1/5 × 40/13

= 0.6153846154

Approximately = 0.6

Therefore, when the two crews start working together, the part of all

the garbage bins that the first garbage truck will empty is 0.6 of the total work done.

Answer:

A) 0.6

Step-by-step explanation:

Differentiate the function.

y = (4x − 1)^2 (4 -x^5)^4

dy/dx=​

Answers

Answer:

[tex]\displaystyle y' = -4(4x - 1)(4 - x^5)^3(22x^5 - 5x^4 - 8)[/tex]

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

BracketsParenthesisExponentsMultiplicationDivisionAdditionSubtractionLeft to Right

Distributive Property

Algebra I

Terms/CoefficientsFactoring

Calculus

Derivatives

Derivative Notation

Derivative of a constant is 0

Basic Power Rule:

f(x) = cxⁿ f’(x) = c·nxⁿ⁻¹

Derivative Rule [Product Rule]:                                                                                [tex]\displaystyle \frac{d}{dx} [f(x)g(x)]=f'(x)g(x) + g'(x)f(x)[/tex]

Derivative Rule [Chain Rule]:                                                                                    [tex]\displaystyle \frac{d}{dx}[f(g(x))] =f'(g(x)) \cdot g'(x)[/tex]

Step-by-step explanation:

Step 1: Define

Identify

y = (4x - 1)²(4 - x⁵)⁴

Step 2: Differentiate

Product Rule:                                                                                                 [tex]\displaystyle y' = \frac{d}{dx}[(4x - 1)^2](4 - x^5)^4 + (4x - 1)^2\frac{d}{dx}[(4 - x^5)^4][/tex]Chain Rule [Basic Power Rule]:                                                                       [tex]\displaystyle y' = [2(4x - 1)^{2 - 1} \cdot \frac{d}{dx}[(4x - 1)]](4 - x^5)^4 + (4x - 1)^2[4(4 - x^5)^{4 - 1} \cdot \frac{d}{dx}[(4 - x^5)]][/tex]Simplify:                                                                                                             [tex]\displaystyle y' = [2(4x - 1) \cdot \frac{d}{dx}[(4x - 1)]](4 - x^5)^4 + (4x - 1)^2[4(4 - x^5)^3 \cdot \frac{d}{dx}[(4 - x^5)]][/tex]Basic Power Rule:                                                                                         [tex]\displaystyle y' = [2(4x - 1) \cdot 4x^{1 - 1}](4 - x^5)^4 + (4x - 1)^2[4(4 - x^5)^3 \cdot -5x^{5 - 1}][/tex]Simplify:                                                                                                          [tex]\displaystyle y' = [2(4x - 1) \cdot 4](4 - x^5)^4 + (4x - 1)^2[4(4 - x^5)^3 \cdot -5x^4][/tex]Multiply:                                                                                                         [tex]\displaystyle y' = 8(4x - 1)(4 - x^5)^4 - 20x^4(4x - 1)^2(4 - x^5)^3[/tex]Factor:                                                                                                           [tex]\displaystyle y' = 4(4x - 1)(4 - x^5)^3 \bigg[ 2(4 - x^5) - 5x^4(4x - 1) \bigg][/tex][Distributive Property] Distribute 2:                                                             [tex]\displaystyle y' = 4(4x - 1)(4 - x^5)^3 \bigg[ 8 - 2x^5 - 5x^4(4x - 1) \bigg][/tex][Distributive Property] Distribute -5x⁴:                                                         [tex]\displaystyle y' = 4(4x - 1)(4 - x^5)^3 \bigg[ 8 - 2x^5 - 20x^5 + 5x^4 \bigg][/tex][Brackets] Combine like terms:                                                                     [tex]\displaystyle y' = 4(4x - 1)(4 - x^5)^3(-22x^5 + 5x^4 + 8)[/tex]Factor:                                                                                                           [tex]\displaystyle y' = -4(4x - 1)(4 - x^5)^3(22x^5 - 5x^4 - 8)[/tex]

Topic: AP Calculus AB/BC (Calculus I/I + II)

Unit: Derivatives

Book: College Calculus 10e

An initial population of 895 quail increases at an annual rate of 7%. Write an exponential function to model the quail population.

Answers

y=895•1.07^x Y is the population of quails and X is the amount of years that have passed.

Find the coordinates of a point that divides the directed line segment XY in the ratio 2:6. answers: A) (3, 5) B) (–1, –3) C) (0, –1) D) (–2, –5)

Answers

Answer:

Option D.

Step-by-step explanation:

Let the coordinates of a point which divides the segment XY in the ratio of m : n is (x, y).

Segment X(-4, -9) and Y(4, 7) has been divided in the ratio of 2 : 6.

Therefore, x = [tex]\frac{[4m+n(-4)]}{m+n}=\frac{8-24}{2+6}[/tex]

                    = -[tex]\frac{16}{8}[/tex]

                    = -2

and y = [tex]\frac{[7m+n(-9)]}{m+n}=\frac{14-54}{2+6}[/tex]

         = [tex]-\frac{40}{8}[/tex]

         = -5

Therefore, the point (x, y) is (-2, -5).

Option D. will be the answer.

In your own words, explain the steps you would need to take to find slope from data in a table.


Answers

The steps that you need is to add subtract and divide all the slopes to get your answer

Answer:

Sample Answer:   Start by choosing two data points. Calculate the difference between the second y value and the first y value. Then divide that by the difference between the second x value and the first x value.

PLEASE I NEED A LOT OF HELP

Answers

Answer:

x = 45°

Step-by-step explanation:

Look at the picture*

Please help me with my Algebra. :)

Answers

Answer:

[tex]\mathrm{D}[/tex]

Step-by-step explanation:

[tex]6x+5y=-2[/tex]

[tex]6(-2)+5(2)=-2[/tex]

[tex]-12+10=-2[/tex]

[tex]-2=-2[/tex]

[tex]\mathrm{Hence,\:it\:is\:true.}[/tex]

Answer:

A

Step-by-step explanation:

What similarity property, if any, can be used to show that the following two triangles are similar

A. Not enough information given

B. AA

C. SAS

D. SSS

Please answer this

Answers

I think it’s SAS maybe

These are my last points. I just wanted to give them away so the first one to answer correctly get the last points.

Answers

Answer:

x=-3

Step-by-step explanation:

\left(5^3\right)^2\cdot 5^{x+4}=5^7

Apply\:exponent\:rule

x+10=7

x=-3

Answer:

x = -3

Step-by-step explanation:

(5^3)^2 · 5^(x+4) = 5^7

First of all, we simplify (5^3)^2. When you have an exponent in parentheses that is raised to another exponent that is outside the parentheses, you multiply the exponents.

(5^3)^2 = 5^(3·2) = 5^6

We cannot simplify 5^(x+4) or 5^7 any further, so our equation is now:

5^6 · 5^(x+4) = 5^7

We can divide 5^6 from both sides to get:

5^(x+4) = (5^7)/(5^6)

When exponents of like terms are divided we can subtract the exponents.

5^(x+4) = 5^(7-6)

5^(x+4) = 5^1

This last part is a bit trickier. When exponents of like terms are multiplied we add the exponents. We can use this knowledge to determine that 5^(x+4) is made up of 5^x · 5^4. Now we have:

5^x · 5^4 = 5^1

We can divide both sides by 5^4.

5^x = (5^1)/(5^4)

We simplify the right side by the same way we did earlier when we divided exponents:

5^x = 5^(1-4)

5^x = 5^-3

We can see that x = -3, but using logarithms, we can finish isolating x. Taking the log base 5 of both sides, we get:

x = log₅(5^-3)

If you don't already know, log₅(5^-3) means what exponent do you raise 5 to in order to get 5^-3. After stating it like this, we can clearly see that log₅(5^-3) equals -3.

So x = -3

Another way we could have solved the logarithm is by using one of the laws of exponents. In this case, we would use logₐ(x^y) = y(logₐm). This would give us:

x = -3(log₅5)

x = -3(1)

x = -3

Either way works.

If you awnser this correctly I will give you more points​

Answers

Answer:

1) 5m-10

Parts, 5m, -10

Operation, Subtraction

Word Expression, 10 less than the product of 5 and m.

Step-by-step explanation:

1) 5m-10

Parts, 5m, -10

Operation, Subtraction

Word Expression, 10 less than the product of 5 and m.

2) 12/2+7

6+7

13

3) 8y-(22)

Terms, 8y, 22

Operation, Subtraction

Word Expression, 22 less than the product of 8 and y.

Answer:

number 2 is 13       and      number 3 is-2.75

Step-by-step explanation:

-2.75

Which expression is equal to (−3x2−2)(4x2+1)? −12x4−11x2−2 −12x4−5x2−2 −12x2−11x−2 12x4−11x2−2

Answers

Answer:

[tex]-12x^4-11x^2-2[/tex]

Explanation:

Step 1 - Expand

[tex](-3x^2-2)(4x^2+1)[/tex]

[tex]-12x^4-3x^2-8x^2-2[/tex]

Step 2 - Combine like terms

[tex]-12x^4-3x^2-8x^2-2[/tex]

[tex]-12x^4-11x^2-2[/tex]

Therefore, the expression that is equal to [tex](-3x^2-2)(4x^2+1)[/tex] is [tex]-12x^4-11x^2-2[/tex].

Answer:

On Edge, the answer is D. 31x2 – 2.

What is the missing number that will complete the
factorization?
6
8
12
24

Answers

Answer:

6

Step-by-step explanation:

6xa is 6a, just like how 2xa is 2a as shown

The answer would is 6

How many solutions does the equation 4x + 8 = − 2 − 2 + 5x have?

Answers

Answer:

12 =x

There is one solution

Step-by-step explanation:

4x + 8 = − 2 − 2 + 5x

Combine like terms

4x+8 = -4+5x

Subtract 4x from each side

4x-4x+8 = -4+5x-4x

8 = -4+x

Add 4 to each side

8+4 = -4+4+x

12 =x

Answer: only one 4x+8=-4+5x

4x-5x=8+4

-1x=12

x=-12

Step-by-step explanation:

8 - n = -4 what does N equal

Answers

Answer:

Make N alone

There is an 8 so we subtract 8 from both sides so the equation is still equal

-4 - 8 = -12

Because we are subtracting N it is positive

N = 12

8 - 12 = -4

Hope this helps

Step-by-step explanation:

The fuel efficiency of passenger cars has increased significantly since the 1970s. A linear model of this situation is given below, where x represents the number of years after 1970, and y represents the average miles per gallon. Interpret the slope.


A. For each year since 1970, passenger car fuel efficiency has increased by 0.29 gallons per mile.

B. For each year since 1970, passenger car fuel efficiency has increased by 13 gallons per mile.

C. For each year since 1970, passenger car fuel efficiency has increased by 0.29 miles per gallon.

D. For each year since 1970, passenger car fuel efficiency has increased by 13 miles per gallon.

Answers

its C not A because

For each year since 1970, passenger car fuel efficiency has increased by 0.29 miles per gallon.

Answer: The answer is C. For each year since 1970, passenger car fuel efficiency has increased by 0.29 miles per gallon.

Step-by-step explanation:

In a linear model of the form y = mx + b, m is the slope and b represents the y-intercept.

In this situation, 0.29 is the slope.

The slope is the ratio of the change in y to the change in x.

In context, the slope indicates an increase of 0.29 miles per gallon per year after 1970.

Therefore, the slope means that for each year since 1970, passenger car fuel efficiency has increased by 0.29 miles per gallon.

what does it mean that the fan data are numerical and univariate?

Answers

Answer:

The fact that the data is univariate means that there is only one variable – age, and the fact the data is numerical means it involves numbers – age.

I'm doing the test and this is what I put for my answer

Other Questions
At a computer store, a customer is considering 7 different computers, 9 different monitors, 8 different printers and 2 different scanners. Assuming that each of the components is compatible with one another and that one of each is to be selected, determine the number of different computer systems possible. When people earn more money, this can have a direct impact on the ______________________ for a particular good or service. *supplyneeddemandopportunity cost Which is a common risk with both tanning and tattoos? Which sentence uses correct spelling?A. Believe me, I definitely would of gone to your wedding, but mycalendar was full,B. Beleive me, I definitely would have gone to your wedding, but mycalender was full.C. Believe me, I defiantly would of gone to your wedding, but mycalendar was full.O D. Believe me, I definitely would have gone to your wedding, but mycalendar was full, According to the video, one of the benefits of carrying things on your head is: a strong neck leaves hands free to do other things helps with balance shows Mayan ancestry If 1.50 L of 0.780 mol/L sodium sulfide is mixed with 1.00 L of a 3.31 mol/L lead(II) nitrate solution, what mass of precipitate would you expect to form? if both the president and the vice president are unable to fulfill their duties who takes over Every organization needs some degree of flexibility and standardization. True False Being overly committed to following rules can harm an organization and keep it from growing. True False Every organization needs either a degree of ________ to adapt to new situations or some degree of ________ to make routine tasks and decisions as efficient and effective as possible. standardization; flexibility culture; vision flexibility; standardization structure; design 3. Which is a qualification for reparations?a You live in the United States,b. you have atleast one ancestor who was enslaved.c. You identified yourself as Alican Americanon a legal document dating back at least 10 years.d. Qualifications have not yet been determined ABC Company keeps their accounting records on the cash basis. During the year, ABC received $260,000 from clients, and ABC paid $85,000 to cover operating expenses. Account balances as of the dates given are as follow: January 1 December 31Accounts Receivable $24,000 $52,000Accrued Liabilities $56,000 $40,000Unearned Service Revenue $35,000 $65,000Prepaid Expenses $26,000 $28,000In addition, depreciation expense for the current year is $16,000.Accrual basis net income is: a. $181,000b. $145,000c. $201,000d. $165,000 5+(85)+728 !? what is the answer please Which expression is equivalent to 2(x+9) + (4x+1)6x+105x+106x+193x-9 Find the cardinal number for the set. = {3, 6, 9, . . . , 36} The company produces two types of goods in quantities of x and y, with market prices of 40 and 80, respectively. If the production cost is given by function C(x,y) =2x^2+5y^2+120 and is not exceeding 250. What is the max profit obtained? Celeste and Dora both offer guitar lessons. Celeste charges an initial fee of $5.00, and an hourly rate of $7.25. Dora has an initial fee of $10.25, and an hourly rate of $6.50. The equation 7.25h + 5 = 6.5h + 10.25 represents the scenario. Select the correct answer.Where should the RUN-ON SENTENCE be divided?I like my dog she licks my hands 2 and rolls 3 over.A.1B. 2C. 3 Imagine that your class has decided to stage a folk dance show titled, Colours of life in the school auditorium. Make a poster for this event. Put in all the necessary details. commonalities used to group languages together include______. Which of the following expressions can be factored by grouping? (Select all that apply.)a^2 - 9 a + 7 ab + 63 b3 a + 4 ab - b - 12ab + 6 b - 2 a - 12x^3 + 9 x^2 + 7 x + 63ay^2 + a - y^2 - 1 What roles did African Americans play in the militaryduring WWI?