Question

分解因式(a+b)^3-(a+b) ,（a-1）^2-9

Answer 1

(a+b)^3-(a+b)

=(a+b)[(a+b)^2-1]

=(a+b)(a^2+2ab+b^2-1)

（a-1）^2-9

=(a-1+3)(a-1-3)

=(a+2)(a-4)