Question

Daca x supra y = 2/3 atunci 3x+y/x+2y =?

Answer 1

$\it \dfrac{x}{y} =\dfrac{2}{3} \Rightarrow \begin{cases}\it x = 2k\\ \\\it y=3k\end{cases},\ \ k\in \mathbb{Q}^{*}\\ \\ \\ \dfrac{3x+y}{x+2y} = \dfrac{3\cdot2k+3k}{2k+2\cdot3k} =\dfrac{9k}{8k} =\dfrac{9}{8}$

Answer 2

x/y=2/3=k

3x=2y=k

x=k/3;

y=k/2;

3x+y/x+2y =k+k/2/(k/3+2*k/2)=3/2k/(4/3k)=3k/2*3k/2=1.

Bafta!