Решите уравнение: 7 1/5:x=9/10.

\[7\frac{1}{5}\ :x = \frac{9}{10}\]

\[x = 7\frac{1}{5}\ :\frac{9}{10} = \frac{36}{5} \cdot \frac{10}{9} = \frac{36 \cdot 10}{5 \cdot 9}\]

\[x = 8.\]