Trang chủ » Hỏi đáp » Môn Toán (3x+1+2/2y+3=3 2(3x+1)-1/2y+3=1 29/11/2023 (3x+1+2/2y+3=3 2(3x+1)-1/2y+3=1
Giải đáp: $x = 0;y = – 1$ Lời giải và giải thích chi tiết: $\begin{array}{l}Dkxd:2y + 3 \ne 0 \Leftrightarrow y \ne – \dfrac{3}{2}\\Dat:\left\{ \begin{array}{l}3x + 1 = a\\\dfrac{1}{{2y + 3}} = b\end{array} \right.\\ \Leftrightarrow \left\{ \begin{array}{l}a + 2b = 3\\2a – b = 1\end{array} \right.\\ \Leftrightarrow \left\{ \begin{array}{l}2a + 4b = 6\\2a – b = 1\end{array} \right.\\ \Leftrightarrow \left\{ \begin{array}{l}5b = 5\\a + 2b = 3\end{array} \right.\\ \Leftrightarrow \left\{ \begin{array}{l}b = 1\\a = 3 – 2b = 1\end{array} \right.\\ \Leftrightarrow \left\{ \begin{array}{l}\dfrac{1}{{2y + 3}} = 1\\3x + 1 = 1\end{array} \right.\\ \Leftrightarrow \left\{ \begin{array}{l}2y + 3 = 1\\3x = 0\end{array} \right.\\ \Leftrightarrow \left\{ \begin{array}{l}2y = – 2 \Leftrightarrow y = – 1\left( {tm} \right)\\x = 0\left( {tm} \right)\end{array} \right.\\Vay\,x = 0;y = – 1\end{array}$ Trả lời
Dkxd:2y + 3 \ne 0 \Leftrightarrow y \ne – \dfrac{3}{2}\\
Dat:\left\{ \begin{array}{l}
3x + 1 = a\\
\dfrac{1}{{2y + 3}} = b
\end{array} \right.\\
\Leftrightarrow \left\{ \begin{array}{l}
a + 2b = 3\\
2a – b = 1
\end{array} \right.\\
\Leftrightarrow \left\{ \begin{array}{l}
2a + 4b = 6\\
2a – b = 1
\end{array} \right.\\
\Leftrightarrow \left\{ \begin{array}{l}
5b = 5\\
a + 2b = 3
\end{array} \right.\\
\Leftrightarrow \left\{ \begin{array}{l}
b = 1\\
a = 3 – 2b = 1
\end{array} \right.\\
\Leftrightarrow \left\{ \begin{array}{l}
\dfrac{1}{{2y + 3}} = 1\\
3x + 1 = 1
\end{array} \right.\\
\Leftrightarrow \left\{ \begin{array}{l}
2y + 3 = 1\\
3x = 0
\end{array} \right.\\
\Leftrightarrow \left\{ \begin{array}{l}
2y = – 2 \Leftrightarrow y = – 1\left( {tm} \right)\\
x = 0\left( {tm} \right)
\end{array} \right.\\
Vay\,x = 0;y = – 1
\end{array}$