Có: \(2x=3y\Leftrightarrow\)\(\frac{x}{3}=\frac{y}{2}\Rightarrow\)\(\frac{x}{21}=\frac{y}{14}\)
\(5y=7z\Leftrightarrow\)\(\frac{y}{7}=\frac{z}{5}\Rightarrow\)\(\frac{y}{14}=\frac{z}{10}\)
=> \(\frac{x}{21}=\frac{y}{14}=\frac{z}{10}\)
Áp dụng tc của dãy tỉ số bằng nhau ta có:
\(\frac{x}{21}=\frac{y}{14}=\frac{z}{10}=\frac{3x-7y+5z}{3\cdot21-7\cdot14+5\cdot10}=\frac{30}{15}=2\)
=> \(\begin{cases}x=42\\y=28\\z=20\end{cases}\)
Ta có: 2x = 3y => x/3 = y/2 = x/21 = y/14
5y = 7z => y/7 = z/5 = y/14 = z/10
=> x/21 = y/14 = z/10
Áp dụng t/c dãy tỉ số bằng nhau, ta có:
\(\frac{x}{21}=\frac{y}{14}=\frac{z}{10}=\frac{3x-7y+5z}{63-98+50}=\frac{30}{15}=2\)
=> \(\begin{cases}x=42\\y=28\\z=20\end{cases}\)
2x = 3y
=> \(\frac{x}{3}=\frac{y}{2}\)
5y = 7x
=> \(\frac{x}{5}=\frac{y}{7}\)
\(\frac{x}{3}=\frac{y}{2},\frac{y}{7}=\frac{z}{5}\)
\(\frac{x}{3}=\frac{y}{2}\Rightarrow\frac{x}{21}=\frac{y}{14}\)
\(\frac{y}{7}=\frac{z}{5}\Rightarrow\frac{y}{14}=\frac{z}{10}\)
\(\frac{x}{21}=\frac{y}{14}=\frac{z}{10}\)
Theo t/c cảu dãy tỉ số bằng nhau ta có :
\(\frac{x}{21}=\frac{y}{14}=\frac{z}{10}=\frac{3x-7y+5z}{63-98+50}=\frac{30}{15}=2\)
\(\frac{x}{21}=2\Rightarrow x=2.21\)
\(\frac{y}{14}=2\Rightarrow\)
\(\frac{z}{10}=2\Rightarrow\)
