Solve the system of equations.
3x - 4y = -10 and 5x + 8y = -2

Question

hero · Answer

3x - 4y = -10
5x + 8y = -2

How come you don't want to learn how to solve these yourself?

anonymous · Answer

Well I WOULD like to, but I'm kind of in a hurry right now.

hero · Answer

You always seem to be in a hurry

anonymous · Answer

Well, I'm actually really in a hurry this time.

anonymous · Answer

3x - 4y = -10 (Eqn. 1)
5x + 8y = -2 (Eqn. 2)

Right. Multiply equation 1 by 2 to get:
6x - 8y = -20
5x + 8y = -2 (Eqn. 2 stays the same)

Now, 8 appears in both equations but they have different signs so add equations 1 and 2 to get:

11x + 0y = -22
11x = -22
x = -2

Sub x = -2 into one of the original equations to find y. We'll use Eqn. 2.

So: 
5x + 8y = -2
5(-2) + 8y = -2
-10 + 8y = -2
8y = 8
y = 1

There we go.

:)

anonymous · Answer

That's the answer...