Toán Lớp 7: Nếu x/y=3/4 và x+y=35 thì bằng bao nhiêu
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Toán Lớp 7: Nếu x/y=3/4 và x+y=35 thì bằng bao nhiêu
Comments ( 2 )
\dfrac{x}{3} = \dfrac{y}{4} = \dfrac{{x + y}}{{3 + 4}} = \dfrac{{35}}{7} = 5\\
\Rightarrow \left\{ \begin{array}{l}
\dfrac{x}{3} = 5\\
\dfrac{y}{4} = 5
\end{array} \right.\\
\Rightarrow \left\{ \begin{array}{l}
x = 5.3\\
y = 5.4
\end{array} \right.\\
\Rightarrow \left\{ \begin{array}{l}
x = 15\\
y = 20
\end{array} \right.
\end{array}$