y=
[tex] \frac{14}{10} = \frac{7}{5} [/tex]
[tex] \frac{y + 9}{15} = \frac{y + 3}{5} [/tex]
[tex] \frac{7}{5} = \frac{y + 3}{5} = y = \frac{7}{5} - \frac{3}{5} [/tex]
The result is very simple now: 4/5