12 = -8x + y
and
12= -6 - 4x - 2y
By substraction eliminate y ,multiplying by 2
24 = -16x + 2y
12 + 6 = -4x - 2y
Then
24 + 18 = -20x
42/-20= x
21/-10= x
Now find y
y= 12 + 8x = 12 + 8(-21/10)
y= 12- 16.8 = -4.8
So then answers are
x= -21/10
y= -4.8
