What is the result of xx−1−11−x\frac{x}{x-1} - \frac{1}{1-x}x−1x−1−x1?
x−1x−1=1\frac{x-1}{x-1} = 1x−1x−1=1
x+1x−1\frac{x+1}{x-1}x−1x+1
x−11−x=−1\frac{x-1}{1-x} = -11−xx−1=−1
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