Áp dụng dãy tĩ số = nhau: \(\dfrac{x}{3}=\dfrac{y}{5}=\dfrac{z}{7}=\dfrac{2x+3y-z}{2.3+3.5-7}=\dfrac{-14}{14}=-1\)
\(\dfrac{x}{3}=-1\Leftrightarrow x=-3\)
\(\dfrac{y}{5}=-1\Leftrightarrow y=-5\)
\(\dfrac{z}{7}=-1\Leftrightarrow z=-7\)
Ta có : \(\dfrac{x}{3}=\dfrac{2x}{6}\)
\(\dfrac{y}{5}=\dfrac{3y}{15}\)
Theo tính chất dãy tỉ số bằng nhau, ta có :
\(\dfrac{2x}{6}=\dfrac{3y}{15}=\dfrac{z}{7}=\dfrac{2x+3y-z}{6+15-7}=\dfrac{-14}{14}=-1\)
Do đó : \(\dfrac{2x}{6}=-1\Rightarrow x=-1.6:2=-3\)
\(\dfrac{3y}{15}=-1\Rightarrow y=-1.15:3=-5\)
\(\dfrac{z}{7}=-1\Rightarrow z=-1.7=-7\)
Vậy x = -3 ; y = -5 ; z = -7
Nhớ tick mk nha !!!
