Giải thích các bước giải:
a)\(
\begin{array}{l}
(\frac{{x + 1}}{{x - 1}} - \frac{{x - 1}}{{x + 1}}):(\frac{2}{{x^2 - 1}} - \frac{x}{{x - 1}} + \frac{1}{{x + 1}}) \\
Đk:x \ne \pm 1 \\
= \frac{{(x + 1)^2 - (x - 1)^2 }}{{{\rm{(x - 1)(x + 1)}}}}:{\rm{[}}\frac{2}{{(x - 1)(x + 1)}} - \frac{{x(x + 1)}}{{(x - 1)(x + 1)}} + \frac{{x - 1}}{{(x + 1)(x - 1)}}{\rm{]}} \\
{\rm{ = }}\frac{{{\rm{x}}^{\rm{2}} + 2x + 1 - x^2 + 2x - 1}}{{(x - 1)(x + 1)}}:\frac{{2 - x^2 - x + x - 1}}{{(x - 1)(x + 1)}} \\
= \frac{{4x}}{{(x - 1)(x + 1)}}.\frac{{(x - 1)(x + 1)}}{{1 - x^2 }} \\
= \frac{{4x}}{{1 - x^2 }} \\
\end{array}
\)
