Question

a. \(\dfrac{x}{-10}\) = \(\dfrac{y}{6}\) và 2x - 3y= 76

b. \(\dfrac{x}{4}\) = \(\dfrac{y}{5}\) và 2x + 5y = 66

Answer 1

a, áp dụng t/c dtsbn ta có:

\(\dfrac{x}{-10}=\dfrac{y}{6}=\dfrac{2x-3y}{2.\left(-10\right)-3.6}-\dfrac{76}{-38}=-2\)

\(\dfrac{x}{-10}=-2\Rightarrow x=20\\ \dfrac{y}{6}=-2\Rightarrow y=-12\)

b, áp dụng t/c dtsbn ta có:

\(\dfrac{x}{4}=\dfrac{y}{5}=\dfrac{2x+5y}{2.4+5.5}=\dfrac{66}{33}=2\)

\(\dfrac{x}{4}=2\Rightarrow x=8\\ \dfrac{y}{5}=2\Rightarrow y=10\)

Answer 2

\(a,\dfrac{x}{-10}=\dfrac{y}{6}=\dfrac{2x-3y}{-20-18}=\dfrac{76}{-38}=-2\\ \Rightarrow\left\{{}\begin{matrix}x=20\\y=-12\end{matrix}\right.\\ b,\dfrac{x}{4}=\dfrac{y}{5}=\dfrac{2x+5y}{8+25}=\dfrac{66}{33}=2\\ \Rightarrow\left\{{}\begin{matrix}x=8\\y=10\end{matrix}\right.\)