Question

Tìm x,y,z biết:a) \(\dfrac{x}{2}=\dfrac{y}{5}=\dfrac{z}{10}\)và y-x=6

Tìm x,y,z biết:b) \(\dfrac{x}{8}=\dfrac{y}{3}=\dfrac{z}{7}\)và x-2y+z=18

 

Answer 1

giúp mình với ạ mình cần gấp

Answer 2

a) Ta có: \(\dfrac{x}{2}=\dfrac{y}{5}\)

⇒\(\dfrac{y-x}{5-2}=\dfrac{6}{3}=2\)

\(\dfrac{x}{2}=2\Rightarrow x=4\)

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

\(\dfrac{z}{10}=2\Rightarrow z=20\)

Answer 3

b) Ta có: \(\dfrac{x}{8}=\dfrac{2y}{6}=\dfrac{z}{7}\)

\(\dfrac{x-2y+z}{8-6+7}=\dfrac{18}{9}=2\)

\(\dfrac{x}{8}=2\Rightarrow x=16\)

\(\dfrac{y}{3}=2\Rightarrow y=6\)

\(\dfrac{z}{7}=2\Rightarrow z=14\)

Answer 4

1. Ta có: \(\dfrac{x}{2}=\dfrac{y}{5}=\dfrac{z}{10}=\dfrac{y-x}{5-2}=\dfrac{6}{3}=2\)

⇒ \(\left\{{}\begin{matrix}x=2.2\\y=2.5\\z=2.10\end{matrix}\right.\)

⇒\(\left\{{}\begin{matrix}x=4\\y=10\\z=20\end{matrix}\right.\)

Vậy x = 4, y = 10, z = 20

2. Ta có: \(\dfrac{x}{8}=\dfrac{y}{3}=\dfrac{z}{7}\)

⇒ \(\dfrac{x}{8}=\dfrac{2y}{6}=\dfrac{z}{7}=\dfrac{x-2y+z}{8-6+7}=\dfrac{18}{9}=2\)

⇒ \(\left\{{}\begin{matrix}x=2.8\\2y=2.6\\z=2.7\end{matrix}\right.\)

⇒ \(\left\{{}\begin{matrix}x=16\\y=6\\z=14\end{matrix}\right.\)

Vậy x = 16, y = 6, z = 14

Học tốt ^^