4(a+2b)²-25(a-b)²
=[2(a+2b)]²-[5(a-b)]²
=[2(a+2b)+5(a-b)][2(a+2b)-5(a-b)]
=(2a+4b+5a-5b)(2a+4b-5a+5b)
=(7a-b)(9b-3a)
=3(7a-b)(3b-a)
明白请采纳,
有新问题请求助,