3. Запишите равенства, обозначив неизвестное через x, и найдите x.

(a) x + 1/2 = 13 1/4 -> x = 13 1/4 - 1/2 = 12 3/4. (b) x - 2 1/3 = 6 2/3 -> x = 6 2/3 + 2 1/3 = 9. (c) x + 11/42 = 4 2/7 -> x = 4 2/7 - 11/42 = 4.