Question

Solve for x and y y+8=-4(x+7)

Answer 1

Because you can't solve for two variables at once, you can guess and trial/error.
You can also give x or y any value, and then solve for the opposite variable.

x = 0
y = -36
for example. There are more solutions.

   y + 8 = -4(x+7)
-36 + 8 = -4(0+7)
      -28 = 0 - 28
      -28 = -28