в) 7$$\frac{14}{25}-\left(3\frac{8}{15}+1\frac{9}{10}\right);

в) $$7\frac{14}{25}-\left(3\frac{8}{15}+1\frac{9}{10}\right)=7\frac{14}{25}-\left(3\frac{16}{30}+1\frac{27}{30}\right)=7\frac{14}{25}-4\frac{43}{30}=7\frac{14}{25}-5\frac{13}{30}=7\frac{84}{150}-5\frac{65}{150}=2\frac{19}{150}$$

Ответ: $$2\frac{19}{150}$$