Question

tìm số nguyên x,y :

a.\(\dfrac{3}{x}=\dfrac{y}{28}=\dfrac{-39}{91}\)

Answer 1

Ta có: \(\dfrac{3}{x}=\dfrac{y}{8}=\dfrac{-39}{91}\)

\(\Rightarrow\) \(\dfrac{3}{x}=\dfrac{y}{8}=\dfrac{-3}{7}\)

\(\Rightarrow\) \(\dfrac{-3}{-x}=\dfrac{\dfrac{y}{4}}{7}=\dfrac{-3}{7}\)

\(\Rightarrow\) \(\left\{{}\begin{matrix}-x=7\\\dfrac{y}{4}=-3\end{matrix}\right.\)

\(\Rightarrow\) \(\left\{{}\begin{matrix}x=-7\\y=-12\end{matrix}\right.\) (TM)

Vậy x = -7; y = -12

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