Пошаговое объяснение:
(51/14)x = 102
x = 102 * 14/51
x = 28
11x + 3 4/7 = 2
11x = 2 - 3 4/7
11x = -1 4/7
x = -1 4/7 : 11
x = -11/7 * 1/11
x = -1/7
(3/8)x + 6/7 = 5 - (5/6)x
(3/8)x + (5/6)x = 5 - 6/7
(9/24)x + (20/24)x = 4 1/7
(29/24)x = 4 1/7
x = 4 1/7 : 29/24
x = 29/7 * 24/29
x = 24/7
x = 3 3/7
21(x - 5) = 2(10 - 7x)
21x - 105 = 20 - 14x
21x + 14x = 20+105
35x = 125
x = 125:35
x = 3 4/7
2/1 ( 2x + 1/3) = 2 1/6 - (x/2 - 5/33)
4x + 2/3 = 2 1/6 - x/2 + 5/33
4x + 2/3 = 2 11/66 + 10/66 - x/2
4x + 44/66 = 2 21/66 - x/2
4x + x/2 = 2 21/66 - 44/66
4x + (1/2)x = 1 43/66
(4 1/2)x = 109/66
x = 109/66 : 4 1/2
x = 109/66 : 9/2
x = 109/66 * 2/9
x = 109/297
8 часов...
потому что день мает 24 часа, а 24/3=8)