Đáp án:
b) \(\left\{ \begin{array}{l}
x = - 1\\
y = 7
\end{array} \right.\)
Giải thích các bước giải:
\(\begin{array}{l}
a)DK:x \ge 1\\
\left\{ \begin{array}{l}
3\sqrt {x - 1} + 2\left| {y + 5} \right| = 13\\
4\sqrt {x - 1} - 2\left| {y + 5} \right| = 8
\end{array} \right.\\
\to \left\{ \begin{array}{l}
7\sqrt {x - 1} = 21\\
4\sqrt {x - 1} - 2\left| {y + 5} \right| = 8
\end{array} \right.\\
\to \left\{ \begin{array}{l}
\sqrt {x - 1} = 3\\
\left| {y + 5} \right| = 2
\end{array} \right.\\
\to \left\{ \begin{array}{l}
x - 1 = 9\\
\left[ \begin{array}{l}
y + 5 = 2\\
y + 5 = - 2
\end{array} \right.
\end{array} \right. \to \left\{ \begin{array}{l}
x = 10\\
\left[ \begin{array}{l}
y = - 3\\
y = - 7
\end{array} \right.
\end{array} \right.\\
b)\left\{ \begin{array}{l}
xy - x - 2y + 2 = xy + 2x - y - 2\\
xy - 4x + 5y - 20 = xy - 3x + 4y - 12
\end{array} \right.\\
\to \left\{ \begin{array}{l}
3x + y = 4\\
x - y = - 8
\end{array} \right.\\
\to \left\{ \begin{array}{l}
4x = - 4\\
x - y = - 8
\end{array} \right.\\
\to \left\{ \begin{array}{l}
x = - 1\\
y = 7
\end{array} \right.
\end{array}\)
