Question

问一道很难的数学题 看看吧

先化简，再求值：（1/a+2-1) / a^2-1/a+2 帮帮忙吧

Answer 1

原式=[(1-a-2)/(a+2)]÷[(a+1)(a-1)/(a+2)]
=[(-a-1)/(a+2)]×[(a+2)/(a+1)(a-1)]
=-(a+1)(a+2)/[(a+2)(a+1)(a-1)]
约分
=-1/(a-1)

Answer 2

-1/a+2 =3.45%