Question 793867
  8x + 8y = -16
-(8x + 9y = -8)
=      -y = -8
        y = 8
solve for x in the first equation
8x + 8(8) = -16
8x + 64 = -16
8x + 64 - 64 = -16 - 64
8x = -80
8x/8 = -80/8
x = -10

check:
8(-10) + 8(8) = -16
-80 + 64 = -16
-16 = -16
8(-10) + 9(8) = -8
-80 + 72 = -8
-8 = -8