问题描述:
1.(2a2-b)-(a2-4b)-(b+c)其中:a=1/3 b=1/2 c=12.2(x3-2y2)-(x-2y)-(x-3y2+2x3)其中:x=-3 y=-2
最佳答案:
1、(2a2-b)-(a2-4b)-(b+c)
=(2a2-a2)+(4b-b-b)-c
=a2+2b-c
=(1/3)2+2×(1/2)-1
=1/9+1-1
=1/9
2、2(x3-2y2)-(x-2y)-(x-3y2+2x3)
=2x3-4y2-x+2y-x+3y2-2x3
= -y2-2x+2y
将x=﹣3,y=﹣2代入“-y2-2x+2y”,得:
-y2-2x+2y
=-(-2)2-2(-3)+2(-2)
= -4+6-4
= ﹣2
? ?