51. Найдите разность: 1) 75 - 3/2; 2) 11/12 - 5/7; 3) 11/12 - 5/7; 4) 9/17 - 8/36.

Решение:

1. \(75 - \frac{3}{2} = \frac{75 \cdot 2 - 3}{2} = \frac{150 - 3}{2} = \frac{147}{2} = 73\frac{1}{2}\)
2. \(\frac{11}{12} - \frac{5}{7} = \frac{11 \cdot 7 - 5 \cdot 12}{84} = \frac{77 - 60}{84} = \frac{17}{84}\)
3. \(\frac{11}{12} - \frac{5}{7} = \frac{11 \cdot 7 - 5 \cdot 12}{84} = \frac{77 - 60}{84} = \frac{17}{84}\)
4. \(\frac{9}{17} - \frac{8}{36} = \frac{9}{17} - \frac{2}{9} = \frac{9 \cdot 9 - 2 \cdot 17}{153} = \frac{81 - 34}{153} = \frac{47}{153}\)

Ответ: 1) \(73\frac{1}{2}\); 2) \(\frac{17}{84}\); 3) \(\frac{17}{84}\); 4) \(\frac{47}{153}\).