Решите уравнение: -7/9-х=-13/18

$- \frac{7}{9-x} = - \frac{13}{8} \\ \\ \frac{7}{9-x} = \frac{13}{8} \\ \\ 13(9-x) = 7*8 \\ \\ 117-13x= 56 \\ \\ 13x= 117-56 \\ \\ 13x= 61 \\ \\ x= 61/13 = 4 \frac{9}{13}$

Проверим:

$- \frac{7}{9-4 \frac{9}{13} } = - \frac{13}{8} \\ \\ - ( 7: 4 \frac{4}{13} ) = - \frac{13}{8} \\ \\ - ( \frac{7}{1} * \frac{13}{56} ) = - \frac{13}{8} \\ \\ - \frac{1*13}{1*8} = - \frac{13}{8} \\ \\ - \frac{13}{8} = - \frac{13}{8}$