各分数式について、分子と分母をそれぞれ因数分解し、共通因数があれば約分します。
(1) (x−1)(x−3)(x−1)(x−2)=x−3x−2 (2) x2(x+2)x(x−2)=x(x+2)x−2 (3) (x+3)(x−5)(x−5)(x+6)=x+3x+6 (4) (x−4)2(x−4)(x+5)=x−4x+5 (5) x2−4x2+2x=(x+2)(x−2)x(x+2)=x−2x (6) x2−6x+9x2−3x=(x−3)2x(x−3)=x−3x (7) x2−5xx2−11x+30=x(x−5)(x−5)(x−6)=xx−6 (8) x2−4x+3x2−x−6=(x−3)(x−1)(x−3)(x+2)=x−1x+2