Ответ:

Треугольники MEF и MEN подобны по двум углам.

\(\frac{8}{x} = \frac{y}{10}\) и \(\frac{8}{21} = \frac{y}{10+y}\),
\(y=\frac{80}{x}\) \(8(10+y)=21y\) => \(80+8y=21y\) => \(80=13y\) => \(y= \frac{80}{13}\)

\(\frac{8}{x}=\frac{\frac{80}{13}}{10} => \frac{8}{x} = \frac{8}{13} => x=13\)

Ответ: x = 13, y = 80/13