Question

[1+3/a-2]÷a+1/a²-4

先化简，再选择一个你喜欢的数（要适合哦！）代入求值

Answer 1

是[1+3/a-2]÷a+1/a²-4？还是[1+3/(a-2)]÷a+1/(a²-4)？
应该是后者吧？
如果是的话：
解：
[1+3/(a-2)]÷a+1/(a²-4)
=[(a-2+3)/(a-2)]÷a+1/(a²-4)
=(a+1)/[a(a-2)]+1/[(a+2)(a-2)]
=[(a+1)(a-2)+a]/[a(a+2)(a-2)]
=(a^2-a-2+a)/[a(a^2-4)]
=(a^2-2)/(a^3-4a)

Answer 2

[1+3/a-2]÷a+1/a²-4
=[(a-2+3)/a-2] *(a²-4)/(a+1)
=(a+1)/(a-2) *(a+2)(a-2)/(a+1)
=a+2
当a=8时
上式=8+2
=10

Answer 3

是这样[1+3/a-2]÷a+1/a²-4还是[1+3/﹙a-2﹚]÷a+1/﹙a²-4﹚