this needs to be solved by "solve with elimination"

Question

-3x-y=8

7x+y=-12

Answer 1

Add the two equations together.

 

 -3x-y=8

+7x+y=-12

--------------

4x = -4

x = -1

 

Substitute this value of x back

 

-3(-1)-y=8

3-y = 8

y = -5

 

So x = -1, y = -5

Answer 2

Hi Lauren, 

In order to use the method of "elimination" we must "remove" the x term or "remove" the y term to solve. 

Step One:

-3x-y=8 We see "-y"

 

7x+y=-12 We see "+y"

We therefore add both of the equations together to cancel out the y terms: 

-3x-y+7x+y=8-12 Now we solve 

-3x+7x=-4 Eliminate the y's because 1y-1y=0

4x=-4 Divide both sides by 4

x=-1

Step Two: We now plug in our x=-1 into either equation to solve for the value of y:

7x+y=-12 

7(-1)+y=-12 Substitute our x value

-7+y=-12 Add 7 to both sides of the equation

y=7-12 

y=-5

∴The value of x is -1 while the value of y is -5.

Best, 

Star

Answer 3

Dear Lauren,

 

-3x-y=8
7x+y=-12

 

Adding the two equations we get,

 

4x = -4

x=-1

 

Substitute -1 in place of x in one of the two equations,

 

7 (-1)+y = -12

-7+y = -12

y=-5

 

So, X=-1, and y = -5

 

I hope it helps,

A

Answer 4

-3x - y = 8

7x + y = -12   

 

Add the two equations

 

4x = 4      divide both sides by 4

x = 1

 

Now substitute 1 for x in either equation and solve for y.