- \(\frac{-3.4}{1\frac1{18}}=-\frac{17}{5}:\frac{19}{18}=-\frac{306}{95}\).
- \(\frac{0.8}{1\frac57}=\frac45:\frac{12}{7}=\frac7{15}\).
- \(40\cdot\left(1\frac28\right)^2-13\cdot\frac18=40\cdot\left(\frac54\right)^2-\frac{13}{8}=\frac{625}{8}-\frac{13}{8}=\frac{153}{2}=76\frac12\).
Ответ: 1) \(-\frac{306}{95}\); 2) \(\frac7{15}\); 3) \(76\frac12\).