Substitute 2x + 14 for y in -4x - y = 4:
-4x - (2x + 14) = 4
-4x - 2x - 14 = 4
-6x - 14 = 4
-6x = 18
x = -3
Substitute -3 for x in y = 2x + 14 and -4x - y = 4:
y = 2(-3) + 14 --> y = -6 + 14 --> y = 8
-4(-3) - y = 4 --> 12 - y = 4 --> -y = -8 --> y = 8
So y = 8