Toán Lớp 9: câu này dễ thôi : ai nhanh nhất 5 sao + cảm ơn nha
x + y = 1
2y – x = 10
–> x = ?
–> y = ?
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Toán Lớp 9: câu này dễ thôi : ai nhanh nhất 5 sao + cảm ơn nha
x + y = 1
2y – x = 10
–> x = ?
–> y = ?
Comments ( 2 )
\left\{ \begin{array}{l}
x + y = 1\left( 1 \right)\\
2y – x = 10\left( 2 \right)
\end{array} \right.\\
\left( 1 \right) + \left( 2 \right) \Leftrightarrow x + y + 2y – x = 1 + 10\\
\Leftrightarrow 3y = 11\\
\Leftrightarrow y = \dfrac{{11}}{3}\\
\left( 1 \right):x + y = 1 \Leftrightarrow x = 1 – y = 1 – \dfrac{{11}}{3} = \dfrac{{ – 8}}{3}\\
Vậy\,\left( {x;y} \right) = \left( {\dfrac{{ – 8}}{3};\dfrac{{11}}{3}} \right)
\end{array}$