ĐKXĐ: \(x\ne0;y\ne0\)
\(\left\{{}\begin{matrix}\dfrac{15}{x}-\dfrac{7}{y}=9\\\dfrac{4}{x}+\dfrac{9}{y}=35\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}\dfrac{60}{x}-\dfrac{28}{y}=36\\\dfrac{60}{x}+\dfrac{135}{y}=525\end{matrix}\right.\)
=>\(\left\{{}\begin{matrix}\dfrac{60}{x}+\dfrac{135}{y}-\dfrac{60}{x}+\dfrac{28}{y}=525-36\\\dfrac{4}{x}+\dfrac{9}{y}=35\end{matrix}\right.\)
=>\(\left\{{}\begin{matrix}\dfrac{163}{y}=489\\\dfrac{4}{x}=35-\dfrac{9}{y}\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}y=\dfrac{1}{3}\\\dfrac{4}{x}=35-9:\dfrac{1}{3}=35-27=8\end{matrix}\right.\)
=>\(\left\{{}\begin{matrix}y=\dfrac{1}{3}\\x=\dfrac{1}{2}\end{matrix}\right.\left(nhận\right)\)
