Решите уравнение: x:7/15=15/28.

\[x\ :\frac{7}{15} = \frac{15}{28}\text{\ \ }\]

\[x = \frac{15}{28} \cdot \frac{7}{15} = \frac{15 \cdot 7}{28 \cdot 15}\]

\[x = \frac{1}{4}.\]