6m(a-x)-8n(a-x) =2(a-x)(3m-4n)3m(x-y)-n(y-x) =3m(x-y)+n(x-y)=(x-y)(3m+n)(a-b)平方（a+b)-(b-a)平方 =(a-b)²(a+b)-(a-b)²=(a-b)²(a+b-1)3x(x-1)立方-6xy(1-x)立方=3x(x-1)³+6xy(x-1)³=...