X-1/X=10又10/11
猜想:x=11,x=-1/11
证明：
X-1/X=10又10/11
(x^2-1)/x=120/11
11(x^2-1)=120x
x^2-120x-11=0
(x-11)(11x+1)=0
x=11,x=-1/11
X-1/X=n又n/(n+1)
(x^2-1)/x=[n(n+1)+n]/(n+1)
(x^2-1)/x=n(n+2)/(n+1)
(n+1)(x^2-1)=n(n+2)x
(n+1)x^2-n(n+2)x-(n+1)=0
利用十字相乘法
[(n+1)x-1]*[x-(n+1)]=0
x=1/(n+1), x=n+1
所以：X-1/X=n又n/(n+1)的解是x=1/(n+1), x=n+1