Задание 3. Найдите значение выражения: 1) 1 / (1/28 + 1/12); 2) 1 / (1/14 - 1/63); 3) 40 * (1/8)^2 - 13 * 1/8

1) 1 / (1/28 + 1/12) = 1 / (3/84 + 7/84) = 1 / (10/84) = 84/10 = 8,4 2) 1 / (1/14 - 1/63) = 1 / (9/126 - 2/126) = 1 / (7/126) = 126/7 = 18 3) 40 * (1/8)^2 - 13 * 1/8 = 40 * (1/64) - 13/8 = 40/64 - 13/8 = 5/8 - 13/8 = -8/8 = -1