Question

I really need some help. I'll mark best answer!

Solve the linear system of equations using the linear combination method.

{8a-4b=20
5a-8b=62

a=?
b=?

Answer 1

multiply top equation by -2, then add equations so b drops out....solve for a...plug in a to get b

Answer 2

Multiply the first equation by -2. This gives you a positive and a negative 8b, which can cancel out, leaving you with -16a = -40 and 5a = 62, which can be added together to make -11a = 22. Divide 22 by -11 to get a alone. A then equals -2. Plug -2 in for a in either equation. Solve for b, giving you -9. Plug these in again just to check if you'd like.

So, as a quick recap, just a is -2 and b is -9. Hope I helped!