Question

mx+nx/my+ ny= .........

Answer 1

mx+nx / (my+ny) = 
x(m+n)/y(m+n) --> cancelando (m+n)...
fica x/y

Answer 2

$\dfrac{mx + nx}{my + ny} \\ \\ \\ \dfrac{x(m + n)}{r(m + n} \\ \\ \\ \dfrac{x(\not m +\not n)}{x( \not m +\not n} \\ \\ \\ =\ \textgreater \ \dfrac{x}{y}$