Jason T. answered 04/30/13
Jason Tutors Math & Physics
First try to find a common factor for the coefficients. There is no common factor other than 1 and -1 for 1, -3 and -3.
Now find the common factor for the exponential expressions x7, x6, x5. These can each be divided by x, x2, x3, x4, and x5. x5 has the largest exponent, so this is the greatest common factor. Now take this common factor "out".
x5( ? - ? - ?) = x7-3x6-3x5. We need to find the right expressions to fill in for ?.
Divide each term in the original by the common factor: x7/x5 = x2. 3x6/x5= 3x. 3x5/x5 = 3
Take our 3 answers and fill them in for the ? and get x5(x2-3x-3).