Giải thích các bước giải:
\(\begin{array}{l}
a.\frac{{2 - x}}{{201}} + \frac{x}{{203}} = \frac{{1 - x}}{{202}} + 1\\
\to \frac{{203.202.2 - 203.202.x + 201.202.x - 201.203 + 201.203.x - 201.202.203}}{{201.202.203}} = 0\\
\to 203.202.2 - 203.202.x + 201.202.x - 201.203 + 201.203.x - 201.202.203 = 0\\
\to 40399x - 8200997 = 0\\
\to x = 203\\
b.DK:x \ne \pm 1\\
\frac{{x - 1}}{{x + 1}} - \frac{{x + 1}}{{x - 1}} = \frac{{ - {x^3} - x + 2}}{{\left( {x - 1} \right)\left( {x + 1} \right)}}\\
\to \frac{{{x^2} - 2x + 1 - {x^2} - 2x - 1 + {x^3} + x - 2}}{{\left( {x - 1} \right)\left( {x + 1} \right)}} = 0\\
\to {x^3} - 3x - 2 = 0\\
\to \left[ \begin{array}{l}
x = 2\\
x = - 1
\end{array} \right.
\end{array}\)
