Question

How do I solve the following problems?

My homework was to correct a puiz that I failed, but I do not know how to solve these problems..please help!

Solving systems of equations using elimination:

7.) 10x - 10y = 0
5x - 4y = 8
Answer (8,8)
I got the right answer because this one was multiple choice, but it was because I guessed...I need to know how to work it out.

8.) -8x - 8y = -8
-5x + 16y = 16

9.)I need this one worked out...I guessed the right answer (7, -7)

2x + 3yy = -7
-3x - 2y = -7

10.) -8x + 8y = -16
-3x + 7y = 10

11. 8x + 14y = 128
6x + 2y