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-4x - 4y = 28

-2x - 4y=32

2007-06-12 02:52:56 · 8 answers · asked by Chamillitary22 1 in Science & Mathematics Mathematics

8 answers

- 4x - 4y = 28- - - - - -Equation 1
- 2x - 4y = 32- - - - - -Equation 2
- - - - - - - - - -

Multiply equation 1 by - 1

- 4x - 4y = 28

- (- 1)(4x) - (- 1)(4y) = - 1(28)

-(- 4x) - (- 4y) = - 28

4x + 4y = - 28
- - - - - - - - - - -

4x + 4y = - 28
- 2x - 4y = 32
- - - - - - - - - - -
2x = 4

2x / 2 = 4/4

x = 4/2

x = 2

Insert the x value into equation 1
- - - - - - - - - - -

- 4x - 4y = 28

- 4(2) - 4y = 28

- 8 - 4y = 28

- 8 - 4y + 8 = 28 + 8

- 4y = 36

- 4y / - 4 = 36 / - 4

y = 36 / - 4

y = - 9

Insert the y value into equation 1
- - - - - - - - - - - -

Check for equation 1

- 4x - 4y = 28

- 4(2) - 4( - 9) = 28

- 8 - (- 36) = 28

- 8 + 36 = 28

28 = 28
- - - - - - - - - - -

Check for equation 2

- 2x - 4y = 32

- 2(2) - 4(- 9) = 32

- 4 - ( - 36) = 32

- 4 + 36 = 32

32 = 32

- - - - - - - - - -

Both equations balance

The solution set { 2, - 9 }

- - - - - - - -s-

2007-06-12 03:32:10 · answer #1 · answered by SAMUEL D 7 · 1 0

If we multiply each term of the second equation by -1, we can write the system as

-4x - 4y = 28
2x + 4y = -32

Then, we can eliminate the variable y by adding like terms of this system of equations.

-2x + 0 = -4

-2x = -4

x = 2

If x = 2 and -4x - 4y = 28, then

-4(2) - 4y = 28

-8 - 4y = 28

-4y = 36

y = -9

So, the solution for this system of linear equations is the ordered pair (x, y) = (2, -9).

2007-06-12 03:02:22 · answer #2 · answered by mathjoe 3 · 0 0

You have
-4x-4y = 28
-2x-4y = 32
substract the second from the first, giving
-2x = -4 , then dividing by -2, yieldx x = 2
Now substitute x=2 into either equation, using the first
-4(x) -4y = 28 or -8-4y = 28, which gives
-4y = 36, dividing by =4 gives y = -9.
substituting these solutions into both equations, proves they are correct.

2007-06-12 03:00:11 · answer #3 · answered by Anonymous · 0 0

-4x - 4y=28
-2x-4y=32

(-2x-4y=32)-1= 2x + 4y= -32

-4x-4y=28
2x+4y=-32

-2x=-4
x=2

-4(2)-4y=28
-8-4y=28
-4y=36
y= -9

x=2 y= -9

2007-06-12 02:59:47 · answer #4 · answered by NOT as smart as a 5th grader 4 · 0 0

4x + 4y = - 28
-2x - 4y = 32----ADD
2x = 4
x = 2
- 8 - 4y = 28
- 36 = 4y
y = - 9
SOLUTION is x = 2 , y = - 9

2007-06-12 03:50:09 · answer #5 · answered by Como 7 · 0 1

when you're turning out to be questions and function the want to make the guidelines integers, try this. verify the answer in improve. x=2, y=3 create the equations: 2x+3y=2(2)+3(3)=13 2x+3y=13 ----(a million) -x+4y=-2+4(3)=10 -x+4y=10 ---(2) 2x+3y = 13 ---- (a million) -x +4y =10 --- (2)

2016-11-23 13:45:28 · answer #6 · answered by Anonymous · 0 0

x=2 y= -9

2007-06-12 03:00:47 · answer #7 · answered by varagani n 1 · 0 0

(-2,9)

2007-06-12 03:00:13 · answer #8 · answered by Anonymous · 0 0

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