a2-2a分之a+2+4-a2分之8)÷a分之a-2=[(a+2)/a(a-2)-8/(a+2)(a-2)] x a/(a-2)=(a+2)/(a-2)²-8a/(a+2)=[(a+2)²-8a]/(a-2)²=(a-2)²/(a-2)²=1
