For 6x+9 = 6x + a, what is the value of a such that there's infinitely many solutions?

1 Answer
Apr 12, 2018

9

Explanation:

If a were any other answer, they wouldn't be equal anymore. If a were 9 however, x could be anything and both sides would be the same.

For example. If we put 9 for a, and then 1 for x, our equation would be 15 = 15. This is a sort of circular equation because it is stating the obvious and not getting you anywhere, but it shows that whatever you put for x one side will force you to getting the same answer on the other side.

Therefore, if a = 9, there would be infinitely many solutions.