Question

For what value of a, would the system have an infinite number of solutions?
2x-y=5
8x-47=2a
A) 2 B) 4 C)5 D)10 E)20

Answer 1

Pick the value that makes them identical in every way.

You have:

2x-7=5
8x-47=2a

A little algebra

2x = 5 + 7 = 12
8x = 2a + 47

Multiply the top one by 4.

8x = 48
8x = 2a + 47

Hmmm... Now what?

Answer 2

@tkhunny i wrote the problem wrong 7 is supposed to be y

Answer 3

Okay, use the same methodology to solve the problem.