Question

[PHAM THI THAO NGUYEN]

x phan 12 = y phan 9 = z phan 5 va xyz =20

Answer 1

[Vũ Trọng Nghĩa]

\(\frac{x}{12}=\frac{y}{9}=\frac{z}{5}=>\frac{xyz}{12.9.5}=\frac{x^3}{12^3}=\frac{20}{540}\Rightarrow x^3=\frac{20.12^3}{540}=64\Rightarrow x=4\)

tự làm tiếp nhé 

\(\frac{xyz}{12.9.5}=\frac{y^3}{9^3}=\frac{20}{540}=>.......y=.......\)

\(\frac{xyz}{12.9.5}=\frac{z^3}{5^3}=\frac{20}{540}=>.....z=......\)

Answer 2

[Nguyễn Quỳnh Chi]

Đặt \(\frac{x}{12}\)=\(\frac{y}{9}\)=\(\frac{z}{5}\)=k

=>x=12k, y=9k, z=5k

Vì xyz=20=> 12k.9k.5k=20

              => 540k³=20

              => k³=\(\frac{1}{27}\)

              => k=\(\frac{1}{3}\)=> x=4, y=3,z=\(\frac{5}{3}\)