Đáp án:
Giải thích các bước giải:
\(\begin{array}{l}
Hpt \to \left\{ \begin{array}{l}
y = 2x + 4\\
\left( {2a + 1} \right)x + 2x + 4 = 2
\end{array} \right.\\
\to \left\{ \begin{array}{l}
y = 2x + 4\\
\left( {2a + 3} \right)x = - 2
\end{array} \right.\\
\to \left\{ \begin{array}{l}
x = - \frac{2}{{2a + 3}}\\
y = 2x + 4 = \frac{{ - 4}}{{2a + 3}} + 4 = \frac{{ - 4 + 8a + 12}}{{2a + 3}}
\end{array} \right.\\
\to \left\{ \begin{array}{l}
x = - \frac{2}{{2a + 3}} < 0\\
y = \frac{{8a + 8}}{{2a + 3}} > 0
\end{array} \right.\\
\to \left\{ \begin{array}{l}
2a + 3 > 0\\
8a + 8 > 0
\end{array} \right. \to a > - 1
\end{array}\)
