[tex] \frac{x}{ \frac{1}{4} } * \frac{y}{ \frac{1}{6} } =>4x=6y ~~|:2=>2x=3y\\
c.m.m.d.c(x;y)=30\\
=>2x=3y=>(2*30*m)=3(30*n)\\
=> 60 m=30n~~|:10~~=>2m=3n=> \left \{ {{m=3} \atop {n=2}} \right. \\
=>2x=3y=>2*90=3*60\\
=>\bold{x=90}~~~si~~~ \bold{y=60}.[/tex]