If is divided by , then for some polynomials . Moreover, (because ), so there exists such that for all . But if we calculate , it turns out that , so .
It does not matter in which order I multiply. I will simply multiply negatives, then positives. -(4)2(3)3(-6)2(-2)4 -48(2)(3)(3)(2)(4) -48(18)(2)(4) -48(18)(8) -48(144) -6,912