Question

Can someone teach me how to solve this equation using substitution or elimination for

{-3x+2y=23
{5x+2y=-17

Answer 1

notice the 2y terms, that suggests if you subtract one equation from another, you eliminate the y term.

Subtract the second from the first.
5x-(-3x)+2y-2y=23-(-17)
8x+0y=40
x=5
now put that into either equation, and solve for y
-3(5)+2y=23
2y=23+15
y=24

Answer 2

eq. 1 says 2y = 3x+23
use that in eq. 2 and you have

5x + 3x+23 = -17

for elimination, this web site gives all the details:

http://www.gregthatcher.com/Mathematics/GaussJordan.aspx