4x - y = 5 --> 4x = y + 5
substitute
4x + 4y = -4
(y + 5) + 4y = -4
5y + 5 = -4
5y = -9
y = -1.8
solve x
4x = y + 5 = -1.8 + 5 = 3.2
x = 3.2/4 = 0.8
