x + 2y = -1
x = -1 - 2y
Let us substitute this value of x in the first equation.
4(-1-2y) - 3y = 18
-4 - 8y - 3y = 18
-11y = 22
11y = -22
y = -2
Let us substitute this value of y in the equation x = -1 -2y.
x = -1 -2(-2)
x = -1 + 4
x = 3
Therefore, x = 3 and y = -2.