x + y = -2 (eq. 1)
2x - y = 14 (eq. 2)
Isolating y from the first equation:
y = -2 - x
Substituting this result into the second equation:
2x - (-2 - x) = 14
2x + 2 + x = 14
3x + 2 = 14
3x = 14 - 2
3x = 12
x = 12/3
x = 4
Then
y = -2 - x
y = -2 - 4
y = -6