Step-by-step explanation: 4x - 3y = -1
3x - 9y = 33
There are several ways to do this. Here is one way:
Get y in terms of x from the top equation.
-3y = -4x - 1
y = (4x + 1)/3 (call this equation E1)
Plug this result for y into the bottom equation, and solve for x.
3x - 9[(4x + 1)/3] = 33
3x - 3(4x + 1) = 33
3x - 12x - 3 = 33
-9x = 36
x = -4
Plug x=-4 into equation E1 and solve for y.
y = [4(-4) + 1]/3 = -15/3 = -5
y = -5
