\[b - \frac{13}{15} = \frac{13}{45}\]
\[b = \frac{13}{45} + \frac{13^{\backslash 3}}{15}\]
\[b = \frac{13 + 39}{45}\]
\[b = \frac{52}{45} = 1\frac{7}{45}\]
\[Ответ:b = 1\frac{7}{45}\text{.\ }\]