I wish I could see your answer in the picture. Then we could put it into the original equation and see if it checks.
It won't, because you made a slight mistake in your first line, where you were
eliminating the parentheses on the right side:
-4(x- 3) = -4x +12 . . . . . not -4x -12 .
That should get you all fixed up.
When you combine like terms from your first line,
your second line will be
4x + 6 = 30 - 4x
and it's all smooth sailing from there.
