Simplify the complex fraction: 1+1x1−1x\frac{1 + \frac{1}{x}}{1 - \frac{1}{x}}1−x11+x1
x+1x−1\frac{x+1}{x-1}x−1x+1
xx−1\frac{x}{x-1}x−1x
1x\frac{1}{x}x1
−1-1−1