[tex]\it\ a)\ \ = \dfrac{51}{14}\cdot \dfrac{7}{17}\cdot \dfrac{2}{3}= \dfrac{51\cdot14}{14\cdot51}=1\\ \\ \\ b)\ \ = \dfrac{\not15\ ^3}{\not8\ ^2}\cdot \dfrac{\not4}{9}\cdot \dfrac{3}{\not25\ ^5}= \dfrac{9}{9\cdot10}= \dfrac{1}{10}\\ \\ \\ c)\ = \dfrac{\not27\ ^9}{\not8\ ^2}\cdot \dfrac{\not4}{\not5}\cdot \dfrac{\not5}{\not3}= \dfrac{9}{2}[/tex]
