3ab-2(a²-ab)-(a²-ab),其中(a-1)²+|b+1|=0 先化简后求值
问题描述:
3ab-2(a²-ab)-(a²-ab),其中(a-1)²+|b+1|=0 先化简后求值
答
(a-1)²+|b+1|=0a-1=0、b+1=0解得:a=1、b=-13ab-2(a²-ab)-(a²-ab)=3ab-3(a²-ab)=3ab-3a²+3ab=6ab-3a²=3a(2b-a)=3×1×[2×(-1)-1]=3×(-3)=-9