=[x(x+1)/(x+1)(x-1) -1/(x+1)(x-1) ÷(x+1)
=(x²+x-1)/(x+1)(x-1)×1/(x+1)
=(x²+x-1)/(x+1)²(x-1) 感觉你的题目不完整大神我也是真么觉得的。。你能带进去数算算嘛