Work Step by Step
Use: $-3x=-4x+x$ $9x^2+12x-3x^3=-3x(x^2-3x-4)=-3x(x^2-4x+x-4)=-3x[x(x-4)+1(x-4)]=-3x(x+1)(x-4)$
You can help us out by revising, improving and updating this answer.Update this answer
After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.