一.化简.5(a+b)²-3(2a+3b)-3(a+b)²+(2a+3b)

问题描述:

一.化简.5(a+b)²-3(2a+3b)-3(a+b)²+(2a+3b)
二.已知(x-6)²+|y+1|=0,求﹙﹣x+2y/3﹚-2/3(x+1/2y)的值
1个回答 分类:数学 2014-11-19

问题解答:

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5(a+b)²-3(2a+3b)-3(a+b)²+(2a+3b)
=5(a+b)^2-6a-9b-3(a+b)^2+2a+3b
=2 (-2 a + a^2 - 3 b + 2 a b + b^2)
(x-6)²+|y+1|=0,
x=6
y=-1
﹙﹣x+2y/3﹚-2/3(x+1/2y)
=(-6-2/3)-2/3(6-1/2)
=-(31/3)
 
 
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