先化简,再求值:5ab²-{a²b-[3ab²-(2ab²-a²b)]},其中a=-3,b=-1
问题描述:
先化简,再求值:5ab²-{a²b-[3ab²-(2ab²-a²b)]},其中a=-3,b=-1
答
5ab²-{a²b-[3ab²-(2ab²-a²b)]}
=5a²b-a²b+3ab²-2ab²+a²b
=5a²b+ab²
=ab(5a+b)
=3×(-15-1)
=-48