System of Linear Equations

through Elimination
Question #1:

Solve the system of equations. Solve for 'x' and 'y' and show your work.

x- y=7
x + y = 5
​

Answer:

C. u^2 + 5u – 6 = 0 where u = (x + 2)

Step-by-step explanation:

(x + 2)^2 + 5(x + 2) – 6 = 0

Let u = x+2

(u)^2 + 5(u) – 6 = 0

Answer:

C.u^2+5u-6=0

Step-by-step explanation:

By comparing (x+2)^2+5(x+2)-6=0 to answer C,that is u^2+5u-6=0,u=(x+2).

By sustituting (x+2)into answer C,we get;

(x+2)^2+5(x+2)-6=0 which is the same as the quadriatic equation given in the question.

Answer:

So you can divide by 2 for the picture. 4/2 = 2

So you can get 2 x 2 picture. The ratio would be 1

if you have a variable it would always be

x by x.

If you want to cover whole wall multiply by 4/3 on the 4 x 4 picture

The original needs to be scaled up by a factor of 75.

Given that, reproducing a 4 cm × 4 cm picture on a 3 m × 3 m wall.

We need to find what ratio we should use.

Ratio, in math, is a term that is used to compare two or more numbers. It is used to indicate how big or small a quantity is when compared to another.

We know that 1 m=100cm, then 3 m=300 cm.

The picture on the wall is (300 cm)/(4 cm) = 75 times as large in each dimension as the original.

Therefore, the original needs to be scaled up by a factor of 75.

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a

because it has the highest values from all the options from all the above

Answer:

y = cos x

Step-by-step explanation:

The graph begins at (0, 1) and completes its first period at (2π, 1)  Thus the period of this function is 2π.  The amplitude is 1; this is the value that y takes on when x = 0.

Thus the equation of this graph is y = 1cos x, or y = cos x.

Answer:

[tex]\fbox{\begin{minipage}{3em}x = 6\end{minipage}}[/tex]

Step-by-step explanation:

Given:

Equation: [tex]3x - 3 = 27 - 2x[/tex]

Solve for:

[tex]x[/tex]

Solution:

Step 1: Select relevant approach:

Let's move all the components containing x to the left side and other components to the right side (notice the change of sign of each one from + to - or - to +), then calculate [tex]x[/tex]

Step 2: Perform the calculation:

      [tex]3x -3 = 27 - 2x[/tex]

Moving components:

<=> [tex]3x + 2x = 27 + 3[/tex]

Adding up components:

<=> [tex]5x = 30[/tex]

Dividing both sides by 5 (coefficient of component containing [tex]x[/tex]:

<=> [tex]\frac{5}{5} x = \frac{30}{5}[/tex]

Simplifying to work out [tex]x[/tex]:

<=>[tex]x = 6[/tex]

Hope this helps!

:)

Answer:

x = 6

Step-by-step explanation:

3x - 3= 27 - 2x

First we put all the x terms to on side, making it 3x + 2x - 3= 27.

Remeber that when we move a term to the other side of the equals sign (=), we change its sign to be the opposite of what it currently is.

Then, we move all the numberics to the other side, so we derieve 3x + 2x = 27 +3. Again, the sign changes when we move it across.

What is left to do is add up the quantities. So 3x + 2x = 5x and 27 +3 = 30.

We are left with 5x = 30. If 5 x's is 30, how much is one? Sinply divide it to get the answer of 30 / 5 which is six!

To make sure the answer is correct substituite 6 in the equation as x and see if its accurate: 3(6) -3 = 7 - 2 (6). And it is!

So x is equal to six.

Answer:

33 1/3 minutes

Step-by-step explanation:

I note x- number of sentences

          y=time

when  x=3, y=1

          x=6, y= 2

           I observe that for every 3 sentences I have one more minute ( y increases by 1)  so y= x/3

when x=99 i have y=99/3=33 minutes

          for x= 100 I have y=100/3minutes= 33  1/3 minutes

Answer:

= -9/2

Step-by-step explanation:

g(x) = -2x^2 -4

Let x = 1/2

g(1/2) = -2 (1/2)^2 -4

        = -2 ( 1/4) - 4

        -1/2 -4

      - 4 1/2

= -9/2

c. 22%

Step-by-step explanation:

sorry for no explanation

Answer:

Equation:  19^2 - 11^2 = width

Step-by-step explanation:

use Pythagorean theorem to find the width.

so, 19^2 - 11^2 = 361-121= 240.

so width = square root of 240

Answer:

19^2 - 11^2 = width

Step-by-step explanation:

Answer:

A

Step-by-step explanation:

If the equation of the line is written in slope-intercept form, y = mx + b then the value of b will be -21; the correct answer is option A.

Slope tells how vertical a line is.

The more the slope is, the more the line is vertical. When slope is zero, the line is horizontal.

To find the slope, we take the ratio of how much the line's height increases as we go forward or backward on the horizontal axis.

This is because the more the height of the line to thee amount we walk or run on the horizontal axis, the more the slope is. That is why we took difference of horizontal axis in denominator and difference of vertical axis on numerator.

Formula for slope, thus, is;

Slope = (y₂ - y₁) / (x₂ - x₁)

Parameters;

J(-4, -5) and K(-6, 3)

= (3 - (-5)) / (-6 - (-4))

= (3 + 5) / (-6 + 4)

= 8 / -2

= -4

Substitute one of the coordinates into the formula to solve for b

y = mx + b

y = -4x + b

3 = -4(-6) + b

3 = 24 + b

3 - 24 = b

b = - 21

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Answer:

Expected Payoff ⇒ $ 1.50 ; Type in 1.50

Step-by-step explanation:

Considering that 1 out of the 100 tickets will have a probability of winning a 150 dollar prize, take a proportionality into account;

[tex]100 - Number of Tickets,\\1 - Number of Tickets You Can Enter,\\\\1 / 100 - Probability of Winning,\\$ 150 - Money Won,\\\\Proportionality - 1 / 100 = x / 150, where x - " Expected Payoff "\\\\1 / 100 = x / 150,\\100 * x = 150,\\\\Conclusion ; x = 1.5 dollars[/tex]

Thus, Solution ; Expected Payoff ⇒ $ 1.50

Answer:

" Expected Payoff " - 17 Dollars ; Type in 17

Step-by-step explanation:

Consider the probability of landing in an odd section;

[tex]Sections of the Wheel - 20 Sections,\\Numbers Numbered On the Wheel - 1 To 20,\\\\Odd Numbers = Even Numbers,\\Odd Numbers = 20 / 2 = 10,\\Even Numbers = Odd Numbers = 10,\\\\Probability of Spinning Even - 10 / 20 = ( Simplified ) 1 / 2,\\Money Won = 34 Dollars,\\\\Proportionality - 1 / 2 = x / 34, Where, x = " Expected Payoff "\\1 / 2 = x / 34,\\2x = 34,\\x = 17 Dollars,\\\\Conclusion ; " Expected Payoff " = 17 Dollars[/tex]

Solution ; Provided Directly Above

Answer:

13

Step-by-step explanation:

1/3 of 6 1/2 multiply by 3/4 (56 divided by 7)  

1/3* 13/2 * 3/4 * 56/7= 1*13*3*56/3*2*4*7= 13*3*56/3*56= 13

Answer:

2/3

Step-by-step explanation:

There are 6 marbles in the jar

4 are not purple

P(not purple) = marbles that are not purple/ total marbles

                      = 4/6 = 2/3

Answer:

2/3

Step-by-step explanation:

since there are 6 total marbles and 4 of them are colors other than purple, there is a 4/6 chance of drawing a marble that is not purple which can be simplified to 2/3.

Answer:

1). Surface area of the prism = 112 cm²

2). Area of the sphere = 615.8 cm²

Step-by-step explanation:

1). Surface area of the triangular prism = Area of the triangular bases + Area of three lateral (rectangular) sides

Area of a triangular base = [tex]\frac{1}{2}(\text{Base})(\text{Height})[/tex]

                                          = [tex]\frac{1}{2}(3)(7)[/tex]

                                          = 10.5 cm²

Area of a rectangle = Length × width

Area of the rectangular lateral sides = (3 × 5) + (8 × 5) + (7 × 5)

                                                            = 15 + 40 + 35

                                                            = 90 cm²

Surface area of the prism = (2 × 10.5) + 90

                                           = 21 + 90

                                           = 112 cm²

2). Surface area of the sphere = 4πr²

                                                  = 4π(7)²

                                                  = 615.75

                                                  ≈ 615.8 cm²  

Answer:

3 normal tickets were sold, 3 tickets were sold for the elderly, and 12 tickets were sold for children

Step-by-step explanation:

Let x = normal ticket number

Let y = child ticket number

Let z = elderly ticket number

The total amount spent is 480, so we can create this equation:

52 * x + 20 * y + 28 * z = 480

They also tell us that each adult took two children, so:

y = 2 * (x + z)

We have two equations and three unknowns, therefore we must simplify and do trial and error. First, let's substitute "y" in terms of "x" and "z" in the first equation, then simplify:

52 * x + 20 * y + 28 * z = 480

52 * x + 20 * 2 * (x + z) + 28 * z = 480

52 * x + 40 * (x + z) + 28 * z = 480

52 * x + 40 * x + 40 * z + 28 * z = 480

92 * x + 68 * z = 480

23 * x + 17 * z = 120

Let's solve for x in terms of e:

23 * x = 120-17 * z

x = (120-17 * z) / 23

We know that (120 - 17 * z) has to be a multiple of 23 for "x" to be an integer. So let's look at testing some values ​​of "z" to make valid values ​​for "x":

120-17 (0) = 120 (not multiple of 23)

120-17 (1) = 103 (not multiple of 23)

120-17 (2) = 86 (not multiple of 23)

120-17 (3) = 69 (multiple of 23)

120-17 (4) = 52 (not multiple of 23)

120-17 (5) = 35 (not multiple of 23)

120-17 (6) = 18 (not multiple of 23)

120-17 (7) = 1 (not multiple of 23)

After that, we get negative values ​​for "x", so here there is only one possible value for "x", so we know that z = 3:

Now we can solve for "x" and "y":

x = (120-17 * 3) / 23

x = (120-51) / 23

x = 69/23

x = 3

Now for and:

y = 2 * (x + y)

y = 2 (3 + 3)

y = 12

Therefore, 3 normal tickets were sold, 3 tickets were sold for the elderly, and 12 tickets were sold for children.

Answer:

x <19.5

Step-by-step explanation:

X-3.3< 16.2

Add 3.3 to each side

X-3.3+3.3< 16.2+3.3

x <19.5

Answer:

10000 ml

Step-by-step explanation:

1 liter =1000 ml

15 -5 = 10

10 * 1000= 10000

46+w=231

w=185

# brown eggs (46) + # white eggs (w) = total # of eggs (231)

Answer:

231 - 46 = 185

Step-by-step explanation:

We know that the restaurant used 231 eggs last week. (That's a lot!)

That is out starting point. It doesn't change.

Then, it says 46 are brown eggs.

To find the number of white eggs, we know it must equal to 231 when added to the 46 brown eggs. Or, 46 + ? = 231.

So, we do the opposite operation of addition; subtraction.

Like this:

231 eggs - 46 brown = ? white eggs.

That equals 185 white eggs.

Keep up the EGGcellent work! ;)

-Bella,

BrainlyBluebell

Answer:

1/8÷7

Step-by-step explanation:

I think

Answer:

C

Step-by-step explanation:

x4(x4-5)+5(x4-5)

=x8-5x4+5x4-25

x8-25

Answer:

The slope is 3.

Step-by-step explanation:

The answer is 3( slope ) because

6÷2=3.

Improper fraction = 3/1

Answer:

3/4

Step-by-step explanation:

Answer:

a. [tex]8x^{2} -14x-15[/tex]

b. [tex](x+3)(x+2)[/tex]

Step-by-step explanation:

A. There are 3 methods (that I know of). The easiest method is the lattice multiplication, while the most commonly used is the FOIL method (First+Outer+Middle+Last)

For F, take the first terms of the 2 and multiply

[tex]4x*2x=8x^{2}[/tex]

For O, take the outer terms and multiply

[tex]4x*-5=-20x[/tex]

For I, take the inner terms and multiply

[tex]3*2x=6x[/tex]

For L, take the last terms and multiply

[tex]3*-5=-15[/tex]

After that, add all of them up

[tex]8x^{2} +(-20x)+6x+(-15)=8x^{2}-14x-15[/tex]

B. Since the equation is in the form x^2+bx+c,

[tex](x+?)(x+?)[/tex]

Now we need to find 2 numbers that will add up to 5 and multiply to 6.

Here are some of the combinations of numbers that multiply to 6

3*2

1*6

-3*-2

-1*-6

3 and 2 add up to 5 so:

[tex](x+3)(x+2)[/tex]

Answer:

1 gram is 0.035274 in ounces

Answer:

It would be about 0.035274

Step-by-step explanation:

For an approximate result, divide the mass value by 28.35

Hope this helps

Answer:

$11.25 / hr

Step-by-step explanation:

36x+40x=855

76x=855

x=11.25

Answer:1/4

Step-by-step explanation:

The slope of a perpendicular line is the "negative reciprocal" of the slope of the original line.

Answer:

160 degrees

Step-by-step explanation:

To change from radians to degrees, multiply by 180 / pi

8 pi/9 * 180/pi

160 degrees

Answer:

4618.1 ft³

Step-by-step explanation:

Volume of the cone:

[tex]V_{cone} = \frac13 \pi r^2 h[/tex]

[tex]V_{cone} = \frac13 \cdot \pi \cdot 49 \cdot 12 = 196\pi[/tex]

Volume of the cilinder:

[tex]V_{cilinder} = \pi r^2 h[/tex]

[tex]V_{cilinder} = \pi \cdot 49 \cdot 22 = 1078\pi[/tex]

Total volume is 2*Vcone + Vcilinder = 1470π ≈ 4618.1 ft³