Question

x/4=y/3=z/2 va 2x+y-2z=21. tìm x; y ;z

Answer 1

\(\frac{x}{4}=\frac{y}{3}=\frac{z}{2}=>\frac{2x}{8}=\frac{y}{3}=\frac{2z}{4}\)

áp dug t/c dãy t/s = nhau ta có:

\(\frac{2x}{8}=\frac{y}{3}=\frac{2z}{4}=\frac{2x+y-2z}{8+3-4}=\frac{21}{7}=3\)

=>x/4=3=>x=12

=>y/3=3=>y=9

=>z/2=3=>z=6

Answer 2

Ta có : \(\frac{x}{4}=\frac{2x}{8};\frac{z}{2}=\frac{2z}{4}\)

Áp dụng tính chất dãy tỉ số bằng nhau ta có :

\(\frac{2x}{8}=\frac{y}{3}=\frac{2z}{4}=\frac{2x+y+2z}{8+3-4}=\frac{21}{7}=3\)

\(\Rightarrow x=12;y=9;z=6\)

Answer 3

Ta có: \(\frac{x}{4}=\frac{y}{3}=\frac{z}{2}=\frac{2x}{8}=\frac{y}{3}=\frac{2z}{4}=\frac{2x+y-2z}{8+3-4}=\frac{21}{7}=3\)

\(\Rightarrow\frac{x}{4}=3\Rightarrow x=12;\frac{y}{3}=3\Rightarrow y=9;\frac{z}{2}=3\Rightarrow z=6\)