Номера 8 и 9 под буквами б,г

Решите задачу:

$(12 \frac{2}{5}-6 \frac{1}{5} ):7 \frac{3}{4} = \frac{4}{5}$
$12 \frac{2}{5}-6 \frac{1}{5}=6 \frac{1}{5}= \frac{31}{5}$
$\frac{31}{5}:7 \frac{3}{4}= \frac{31}{5}: \frac{4}{31}= \frac{4}{5}$

$2 \frac{1}{3}* \frac{6}{7}-2 \frac{1}{4}:5 \frac{3}{4}= \frac{14}{23}$
$2 \frac{1}{3}* \frac{6}{7}= \frac{7}{3}* \frac{6}{7}= \frac{6}{3} =2$
$2 \frac{1}{4}:5 \frac{3}{4}= \frac{9}{4}* \frac{4}{23}= \frac{9}{23}$
$2- \frac{9}{23}= \frac{46-9}{23} = \frac{37}{23}=1 \frac{14}{23}$