Question

先化简后求值(2a的平方-b)-(a的平方-4b)-(b+c),其中a=三分之一,b=二分之一,c=1

Answer 1

解

(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