(a-b)^2-1 81(a-b)^2-16(a+b)^2 因式分解
2个回答

1、(a-b)²-1=(a-b+1)(a-b-1)

2、81(a-b)²-16(a+b)²

=[9(a-b)+4(a+b)][9(a-b)-4(a+b)]

=(9a-9b+4a+4b)(9a-9b-4a-4b)

=(13a-5b)(5a-13b)

3、-49+16a²b²

=(4ab)²-7²

=(4ab+7)(4ab-7)