Question

If you multiply the first equation by 6, the following system is the result.

3x + 9y = -42
-3x + 2y = -2

To solve this system by elimination, the equations.

Answer 1

Elimination means you’re adding/subtracting the equations such that one of the variables is cancelled out. You’re left with one equation and one variable which can then be solved.

In this case you can add the two equations so that the terms with x cancel:

3x + 9y = -42
-3x + 2y = -2
———————
0 + 11y = -44
y = -4

Then plug y back into either original equation to solve for x. I’ll use the first:

3x + 9(-4) = -42
3x - 36 = -42
3x = -6
x = -2