化简,求值:(a²-b²)/(a b) (a²-2ab b²)/(a-b),其中a=0.5,b=-2

题目

化简,求值:(a²-b²)/(a b) (a²-2ab b²)/(a-b),其中a=0.5,b=-2

答案

(a²-b²)/(a+b)+(a²-2ab+b²)/(a-b)
=(a+b)(a-b)/(a+b)+(a-b)²/(a-b)
=a-b+a-b
=2a-2b
=2×0.5-2×(-2)
=1+4
=5