6 (x-6) = - 3 (-x + 3)

You have to distribute!

6 (x) = 6x and 6 (-6) = -36

So now you have 6x-36=-3 (-x+3)

Now do the same on the other side.

-3 (-x) = 3x - 3 (3) = -9

So now, 6x-36=3x-9

Combine the like terms:

Subtract 3x in both sides.

6x-3x=3x

Now: 3x-36=-9

Add 36 in both sides.

3x=27

Divide by 3 on both sides to get x alone.

3x/3 = x 27/3=9

X=9