Đáp án:
\(\left\{ \begin{array}{l}
x = 0\\
y = -3
\end{array} \right.\)
Giải thích các bước giải:
\(\begin{array}{l}
\left\{ \begin{array}{l}
7{x^2} + 13y = - 39\\
5{x^2} - 11y = 33
\end{array} \right.\\
\to \left\{ \begin{array}{l}
77{x^2} + 143y = - 429\\
65{x^2} - 143y = 429
\end{array} \right.\\
\to \left\{ \begin{array}{l}
142{x^2} = 0\\
5{x^2} - 11y = 33
\end{array} \right.\\
\to \left\{ \begin{array}{l}
{x^2} = 0\\
y =- \dfrac{{33}}{{11}}
\end{array} \right.\\
\to \left\{ \begin{array}{l}
x = 0\\
y = -3
\end{array} \right.
\end{array}\)
