Question

calcula (x+y)
si: xy en base 9 es igual a yx en base 7

Answer 1

$Hola! \\ \\ Resolviendo~como~indica: \\ \\ xy_{(9)}=yx_{(7)} \\ \\ 9x+y=7y+x \\ \\ 9x-x=7y-y \\ \\ 8x=6y \\ \\ \frac{y}{x}= \frac{4}{3} =\ \textgreater \ \begin{cases}x=3 \\ \\ y=4\end{cases} \\ \\ Nos~pide~calcular: \\ (x+y)=3+4=\ \textgreater \ \boxed{\boxed{(x+y)=7}}$