[tex] \frac{x}{5} = \frac{y}{7}=k. \\ \frac{x}{5}= k =\ \textgreater \ x=5k \\ \frac{y}{7} =k =\ \textgreater \ y= 7k. \\ \frac{x+y}{2}=29,4. \\ \frac{5k+7k}{2} =29,4. \\ \frac{12k}{2}= 29,4. \\ 6k= 29,4. \\
k= \frac{29,4}{6} \\ k= 4.9 \\ x=5k = 5*4,9
\\ \boxed {x=24,5} \\ y=7k=4,9*7 \\ \boxed{ y=34,3} [/tex]
