Question

tìm x,y,z biết:

\(\frac{x}{2}=\frac{y}{3}=\frac{z}{5}\)và x*y*z=810

Answer 1

\(\frac{x}{2}=\frac{y}{3}=\frac{z}{5}=\frac{x.y.z}{2.3.5}=\frac{810}{30}=27\)

\(\Rightarrow\frac{x}{2}=27\Leftrightarrow x=27.2=54\)

\(\Rightarrow\frac{y}{3}=27\Leftrightarrow y=27.3=81\)

\(\Rightarrow\frac{z}{5}=27\Leftrightarrow z=27.5=135\)

Vậy x = 54 ; y = 81 ; z = 135

Answer 2

Ta có: x/2=y/3=z/5=a (a khác 0)

Suy ra: x=2a;y=3a;z=5a

Suy ra:x*y*z=2a*3a*5a=2*3*5*a*a*a=30a³=810

Suy ra:a³=810:30=27.

Suy ra:a=3

Suy ra: x=3*2=6

          y=3*3=9

          z=3*5=15