Question

Tìm x, y, z biết:

Answer 1

\(\Rightarrow\dfrac{x}{9}=\dfrac{y}{12}=\dfrac{z}{20}\)

Áp dụng t/c dtsbn:

\(\dfrac{x}{9}=\dfrac{y}{12}=\dfrac{z}{20}=\dfrac{2x}{18}=\dfrac{3y}{36}=\dfrac{2x-3y+z}{18-36+20}=\dfrac{6}{2}=3\)

\(\Rightarrow\left\{{}\begin{matrix}x=3.9=27\\y=3.12=36\\z=3.20=60\end{matrix}\right.\)

Vậy...

Answer 2

Lời giải:

ĐKĐB $\Rightarrow \frac{x}{9}=\frac{y}{12}=\frac{z}{20}$

Ta có:

$\frac{x}{9}=\frac{y}{12}=\frac{z}{20}$

$=\frac{2x}{18}=\frac{3y}{36}=\frac{z}{20}$

$=\frac{2x-3y+z}{18-36+20}=\frac{6}{2}=3$ 

$\Rightarrow x=9.3=27; y=12.3=36; z=20.3=60$