Question

(x-1)/2 =(y+3)/4 = (z-5)/6 và 5z -3x-4y=50

 

Answer 1

\(\dfrac{x-1}{2}=\dfrac{y+3}{4}=\dfrac{z-5}{6}=\dfrac{-3x+3}{-6}=\dfrac{4y+12}{16}=\dfrac{5z-25}{30}=\dfrac{5z-25-3z+3-4y-12}{30-6-16}=\dfrac{50-34}{8}=2\)

\(\Rightarrow\left\{{}\begin{matrix}x=2.2+1=5\\y=2.4-3=5\\z=2.6+5=17\end{matrix}\right.\)

Answer 2

Áp dụng t/c dtsbn:

\(\dfrac{x-1}{2}=\dfrac{y+3}{4}=\dfrac{z-5}{6}=\dfrac{3x-3}{6}=\dfrac{4y+12}{16}=\dfrac{5z-25}{30}=\dfrac{5x-25-\left(3x-3\right)-\left(4y-12\right)}{30-16-6}=\dfrac{\left(5x-3x-4y\right)-\left(25-3-12\right)}{8}=\dfrac{50-10}{8}=5\)

\(\Rightarrow\left\{{}\begin{matrix}x-1=10\\y+3=20\\z-5=30\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x=11\\y=17\\z=35\end{matrix}\right.\)