先化简,后求值:a2-2a+1分之a2-1+a-2分之2a-a2÷a,其中a=2分之3
问题描述：
先化简,后求值:a2-2a+1分之a2-1+a-2分之2a-a2÷a,其中a=2分之3
答
原式=[(a²-1)/(a²-2a+1)]+[(2a-a²)/(a-2)]÷a=[(a+1)(a-1)/(a-1)²]+[-a(a-2)/(a-2)]×(1/a)=[(a+1)/(a-1)]-1=[(a+1)/(a-1)]-[(a-1)/(a-1)]=[(a+1)-(a-1)]/(a-1)=(a+1-a+1)/(a-1)=2/(a-1)当a=3/2...