我很PL哦
幼苗
共回答了15个问题采纳率:93.3% 举报
①(1-x²)(1-y²)-4xy
=1-y²-x²+x²y²-4xy
=(1-2xy+x²y²)-(x²+y²+2xy)
=(1-xy)²-(x+y)²
=(1-xy+x+y)(1-xy-x-y)
②(a+b)²+4(a+b+1)
=(a+b)²+4(a+b)+4
=(a+b+2)²
③1+36a²b²-4a²-9b²
=(1-9b²)-(4a²-36a²b²)
=(1-9b²)-4a²(1-9b²)
=(1-9b²)(1-4a²)
=(1+3b)(1-3b)(1+2a)(1-2a)
1年前
1