Вычислите: $$1\frac{28}{17}:1\frac{5}{51}-\frac{3}{4}\cdot\left(3-1\frac{8}{15}\right)$$.

Выполним вычисления по действиям:

1. $$3 - 1\frac{8}{15} = 3 - \frac{23}{15} = \frac{45}{15} - \frac{23}{15} = \frac{22}{15}$$
2. $$\frac{3}{4} \cdot \frac{22}{15} = \frac{1}{2} \cdot \frac{11}{5} = \frac{11}{10} = 1\frac{1}{10}$$
3. $$1\frac{28}{17} : 1\frac{5}{51} = \frac{45}{17} : \frac{56}{51} = \frac{45}{17} \cdot \frac{51}{56} = \frac{45}{1} \cdot \frac{3}{56} = \frac{135}{56} = 2\frac{23}{56}$$
4. $$2\frac{23}{56} - 1\frac{1}{10} = 2\frac{115}{280} - 1\frac{28}{280} = 1\frac{87}{280}$$

Ответ: $$1\frac{87}{280}$$