Answer :
Answer:
x = -9 1/2
y = -16 1/2
Step-by-step explanation:
x - y = 7
solve the above for 'y': -y = 7 - x
multiple each side by -1: y = x - 7
now both equations are in 'y=' form
x - 7 = 3x + 12
-2x - 7 = 12
-2x = 19
x = -19/2 or -9 1/2
-9.5 - y = 7
-y = 16.5
y = -16.5 or -16 1/2