Solution
(x−4)(x−5)(x−6)(x−1)(x−2)(x−3)
Since degrees are equal, divide first.
(x−4)(x−5)(x−6)(x−1)(x−2)(x−3)=1+(x−4)(x−5)(x−6)R(x)
Now let:
(x−4)(x−5)(x−6)(x−1)(x−2)(x−3)=1+x−4A+x−5B+x−6C
Solving gives A=3, B=−24, C=30.
(x−4)(x−5)(x−6)(x−1)(x−2)(x−3)=1+x−43−x−524+x−630