how to work this problem

Question

3x-y=-8

5x+2y=5

Answer 1

Hi Britt--

 

you want to stack them up and add them so you can eventually eliminate one of the variables. So start here:

 

    3x - y = -8

+  5x + 2y = 5

 

= 8x + y = -3

 

so y = -3 - 8x, so wherever you see a y, sub in -3 - 8x.

 

SO, 3x - -3 -8x = -8

 

then combine terms, SO...

 

-5x = -5, so ... x = -1

 

and y = -3 - 8x, so y = -3 - (-8), or y = -3 + 8, OR... y = 5.

 

Now plug them in to the original equations and see if they work... (Hint: they do... :-)  )

 

Hope this helps!

 

Matt