Bài 4:
a) Áp dụng t/c dtsbn:
\(\dfrac{x}{4}=\dfrac{y}{3}=\dfrac{x+y}{4+3}=\dfrac{14}{7}=2\Rightarrow\left\{{}\begin{matrix}x=2.4=8\\y=2.3=6\end{matrix}\right.\)
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b) Áp dụng t/c dtsbn:
\(\dfrac{x}{8}=\dfrac{y}{12}=\dfrac{2x}{16}=\dfrac{3y}{36}=\dfrac{2x+3y}{16+36}=\dfrac{13}{52}=\dfrac{1}{4}\)
\(\Rightarrow\left\{{}\begin{matrix}x=\dfrac{1}{4}.8=2\\y=\dfrac{1}{4}.12=3\end{matrix}\right.\)(nhận)
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