This is one of the questions I had trouble with. The mistake I was making was that when I separated the coefficient from the x2 to make the polynomial easy and not ugly, I did not divide the rest of the terms by the coefficient.
The incorrect factoring of this expression is,
The correct factoring of the expression is,
After I divided the other terms by the coefficient, I put x in both brackets, then listed the factor of 3; 3 x 1, -3 x -1, -3 x 1, and 3 x -1. I knew the product also had to equal -4, so I chose -3 x -1 because -3 x -1 = 3, and -3 + -1 = -4.