Решите систему уравнений: 5x+3y=4; 2x-y=-5.

Ответ:

\[\left\{ \begin{matrix} 5x + 3y = 4\ \\ 2x - y = - 5 \\ \end{matrix} \right.\ \text{\ \ \ \ \ \ \ \ \ \ \ }\left\{ \begin{matrix} y = 2x + 5\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \\ 5x + 3(2x + 5) = 4 \\ \end{matrix} \right.\ \]

\[5x + 6x + 15 = 4\]

\[11x = 4 - 15\]

\[11x = - 11\]

\[x = - 1.\]

\[\left\{ \begin{matrix} x = - 1\ \ \ \ \ \ \ \ \\ y = - 2 + 5 \\ \end{matrix} \right.\ \text{\ \ \ \ \ \ \ \ \ }\left\{ \begin{matrix} x = - 1 \\ y = 3\ \ \ \\ \end{matrix} \right.\ \]

\[Ответ:( - 1;3).\]