You can put this solution on YOUR website! the problem is:
-3x * (x-3)
you distribute as follows:
(-3x * x) + (-3x * -3)
you then simplify this to:
(-3x^2) + (9x) which becomes:
-3x^2 + 9x
your answer is:
-3x*x - -3x*3
this simplifies to:
-3x^2 + 9x
looks good to me.