2x-12=-2(x^2-3x)^(.5)

1) divide by -2 by the associative property of mult.

2) that makes -x+6=(x^2-3x)^(.5), then square both sides

3) that makes, x^2-12x+36=(x^2-3x)

4) then, subtract x^2 and x^2, and divide -3 and -12 to make 4 and subtract 36.

5) that makes 4x=x-36, so subtract x to make 3x=-36 and divide by 3 to make x=-12 but the answer is x=4. What happened?

It seems to me like all the properties of numbers and order of operations were followed