Ответ:

а)

\(1\frac{5}{17}=\frac{22}{17}\), \(2\frac{4}{11}=\frac{26}{11}\).

\[\frac{22}{17}\cdot\left(7-\frac{26}{11}\right)=\frac{22}{17}\cdot\frac{51}{11}=6.\]

б)

\[42:1.2-1.05:1.6=35-0.65625=34.34375.\]

Ответ: а) 6; б) 34,34375.