Question

先化简3x+3/x^2-1-2/x-1,然后选择一个合适的你最喜欢的x值，代入求值

Answer 1

(3x+3)/(x^2-1)-2/(x-1)
=3(x+1)/(x+1)(x-1)-2/(x-1)
=3/(x-1)-2/(x-1)
=1/(x-1)
当x=8时 上式得：
1/（8-1）=1/7

Answer 2

(3x+3)/(x^2-1)-2/(x-1)=3/(x-1)-2/(x-1)=1/(x-1)
x-1≠0, x≠1.
当x=2时，原式=1。