(a+2b)(a-2b)+(a-2b)^2-(6a^2b-2ab^2)/2b,其中|a-3分之1|+(b+2)^2=0
问题描述：
(a+2b)(a-2b)+(a-2b)^2-(6a^2b-2ab^2)/2b,其中|a-3分之1|+(b+2)^2=0
先化简再求值
答
|a-1/3|=0 a=1/3
(b+2)^2=0 b=-2
(a+2b)(a-2b)+(a-2b)^2-(6a^2b-2ab^2)/2b
=a^2-4b^2+a^2-4ab+4b^2-3a^2+ab
=-a^2-3ab
=-(1/3)^2-3(1/3)(-2)
=-1/9+2
=17/9