Question

Answer 1

Đặt \(\dfrac{x}{-4}=\dfrac{y}{-7}=\dfrac{z}{3}=k\)

\(\Leftrightarrow\left\{{}\begin{matrix}x=-4k\\y=-7k\\z=3k\end{matrix}\right.\)

Ta có: \(A=\dfrac{-2x+y+5z}{2x-3y-6z}\)

\(=\dfrac{-2\cdot\left(-4k\right)+\left(-7k\right)+5\cdot3k}{2\cdot\left(-4k\right)-3\cdot\left(-7k\right)-6\cdot3k}\)

\(=\dfrac{16k}{3k}=\dfrac{16}{3}\)