Tìm x,y $\frac{x-y}{3}$ =$\frac{x+y}{15}$ =$\frac{x.y}{200}$

$\frac{x-y}{3}$$=$$\frac{x+y}{15}$

$⇒$ $\frac{2x}{18}$ $=$ $\frac{xy}{200}$ 

$⇒400x=18xy$

$⇒400=18y$

$⇒y=$$\frac{200}{9}$

$Ta $ $có$ $\frac{x+y}{15}$ $=$ $\frac{xy}{200}$ 

$⇒$ $\frac{x+\frac{200}{9} }{15}$ $=$ $\frac{x}{9}$

$⇒$ $x=$ $\frac{100}{3}$ 

$Vậy$ $\left \{ {{x=\frac{100}{3}} \atop {y=\frac{200}{9}}} \right.$