先化简后求值:a-1/2(4a-b)+3(a-1/2b);其中a、b满足(a-1/2)^2+|b+1|=0

问题描述:

先化简后求值:a-1/2(4a-b)+3(a-1/2b);其中a、b满足(a-1/2)^2+|b+1|=0

(a-1/2)^2>=0
|b+1|>=0
a=1/2
b=-1
a-1/2(4a-b)+3(a-1/2b)=2

(a-1/2)^2+|b+1|=0
(a-1/2)^2>=0
|b+1|>=0
所以a=1/2 b=-1
所:a-1/2(4a-b)+3(a-1/2b)=a-2a+b/2+3a-3/2b=2a-b=2*1/2+1=2