还有什么地方不是很明白
1)=x^2(a-b)-(a-b)=(a-b)(x^2-1)=(a-b)(x+1)(x-1) 2)=[5(a+b)]^2 -[3(a-b)]^2 =(5a+5b+3a-3b)(5a+5b-3a+3b) =(8a+2b)(2a+8b) =4(4a+b)(a+4b)
