10 - 3(3x - 40) = -9x a)x = -9 b)no solution c)x = 10 d)all real numbers

Remove the brackets on the left
10 - 9x + 120 = - 9x You get a bizarre result no matter what you try to do to resolve this. If you say any number will do pick, a number at random for x. Say 10

10 - 90 + 120 = -90 Is this statement true? No. You only need 1 exception but 0 is a popular number to look for answers. Will it work?
10 - 0 + 120 = 0 That doesn't work either.

There is no number you could pick that that would give you anything but 10 + 120 = 0

B <<<<<< No Solution 

The answer is part a: use