Giải thích các bước giải:
\(\begin{array}{l}
a.\left[ \begin{array}{l}
{x^2} + x - 2 = x\\
{x^2} + x - 2 = - x
\end{array} \right.\\
\to \left[ \begin{array}{l}
{x^2} + 2 = 0\left( {voli} \right)\\
{x^2} + 2x - 2 = 0
\end{array} \right.\\
\to \left[ \begin{array}{l}
x = - 1 + \sqrt 3 \\
x = - 1 - \sqrt 3
\end{array} \right.\\
b.\sqrt {x - 1} = x - 3\\
\to \left\{ \begin{array}{l}
x \ge 1\\
x - 1 = {x^2} - 6x + 9
\end{array} \right.\\
\to \left\{ \begin{array}{l}
x \ge 1\\
\left( {x - 5} \right)\left( {x - 2} \right) = 0
\end{array} \right.\\
\to \left\{ \begin{array}{l}
x \ge 1\\
\left[ \begin{array}{l}
x = 5\\
x = 2
\end{array} \right.\left( {TM} \right)
\end{array} \right.
\end{array}\)
