Giải thích các bước giải:
$\begin{array}{l}
\left\{ \begin{array}{l}
\frac{{5x}}{{x + 1}} + \frac{y}{{y - 3}} = 27\\
\frac{{2x}}{{x + 1}} - \frac{{3y}}{{y - 3}} = 4
\end{array} \right. \Rightarrow \left\{ \begin{array}{l}
\frac{{5\left( {x + 1} \right) - 5}}{{x + 1}} + \frac{{y - 3 + 3}}{{y - 3}} = 27\\
\frac{{2\left( {x + 1} \right) - 2}}{{x + 1}} - \frac{{3\left( {y - 3} \right) + 9}}{{y - 3}} = 4
\end{array} \right.\\
\Rightarrow \left\{ \begin{array}{l}
5 - \frac{5}{{x + 1}} + 1 + \frac{3}{{y - 3}} = 27\\
2 - \frac{2}{{x + 1}} - 3 - \frac{9}{{y - 3}} = 4
\end{array} \right.\\
\Rightarrow \left\{ \begin{array}{l}
- 5.\frac{1}{{x + 1}} + 3.\frac{1}{{y - 3}} = 21\\
- 2.\frac{1}{{x + 1}} - 9.\frac{1}{{y - 3}} = 5
\end{array} \right.\\
\Rightarrow \left\{ \begin{array}{l}
\frac{1}{{x + 1}} = - 4\\
\frac{1}{{y - 3}} = \frac{1}{3}
\end{array} \right.\\
\Rightarrow \left\{ \begin{array}{l}
x + 1 = - \frac{1}{4}\\
y - 3 = 3
\end{array} \right.\\
\Rightarrow \left\{ \begin{array}{l}
x = - \frac{5}{4}\\
y = 6
\end{array} \right.\left( {tmdk} \right)
\end{array}$
