You can put this solution on YOUR website! -3x^3 - 6x^2 + 189x
-3x(x^2+2x-63)=0
-3x(x^2+9x-7x-63)=0
-3x(x(x+9)-7(x+9))=0
-3x(x-7)(x+9)=0
(x-7)(x+9)=0/-3x
(x-7)(x+9)=0
x=7 or-9
The problem asks to factor completely.
Instead, @mananth solved an equation, and got an incomplete solution.
Thus, the requested assignment was not done in accordance with the request.