Question

x/3 = y/4=z/5 va x.y.z =480

 

Answer 1

Đặt: \(\frac{x}{3}=\frac{y}{4}=\frac{z}{5}=k\) =>

\(x=3k\)\(y=4k\)\(z=5k\)

=> \(3k.4k.5k=x.y.z\)

=> \(\left(3.4.5\right).k^3=480\)

=> \(60.k^3=480\)

=> \(k^3=\frac{480}{60}=8\)

=> \(k=2\)

Từ đó suy ra: \(\frac{x}{3}=\frac{y}{4}=\frac{z}{5}=2\)

=> \(x=3.2=6\)

=> \(y=4.2=8\)

=> \(z=5.2=10\)

Answer 2

Đặt k = \(\dfrac{x}{3}=\dfrac{y}{4}=\dfrac{z}{5}\)

\(\Rightarrow x=3k,y=4k,z=5k\)

Từ x.y.z = 480, ta có:

3k.4k.5k = 480

\(\Rightarrow60k^3\) = 480

\(\Rightarrow k^3=8\)

\(\Rightarrow k=2\)

Với k = 2 \(\Rightarrow\) x = 6, y = 8, z = 10