your question:
solve by elimination x+7y=17 x-y=-7
answer:
x+7y=17
x-y=-7
change signs on bottom equation
x+7y=17
-x+ y= +7
8y = 24
---. -----
8. 8
y= 3
plug y into one of the original equations
x -3 = -7
+3. +3
x=-4
(-4,3)
hope this helps! have a great day! :)