\left \{ {{x-y=39 } \atop {\frac{x}{y}=\frac{5}{2}}} \right.
\left \{ {{x-y=39 } \atop {x=\frac{5}{2}y}} \right.
\left \{ {{\frac{5}{2}y-y=39 } \atop {x=\frac{5}{2}y}} \right.
\left \{ {{2\frac{1}{2}y-y=39 } \atop {x=\frac{5}{2}y}} \right.
\left \{ {{1\frac{1}{2}y=39 } \atop {x=\frac{5}{2}y}} \right.
\left \{ {{\frac{3}{2}y=39 } \atop {x=\frac{5}{2}y}} \right.
\left \{ {{y=39*\frac{2}{3} } \atop {x=\frac{5}{2}y}} \right.
\left \{ {{y=26 } \atop {x=65}} \right.