4x – 3y = –1 3x – 9y = 33

Question

What is the solution to the system of equations? Please help i am very confused.

Answer 1

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

Test the solution.