(5/7-2/3x)×21=1 Решите уравнение
5/7 - 2/3х = 1/21 15/21 - 2/3х = 1/21 2/3х = 14/21 х = 14/21 : 2/3 14/21 : 2/3 = 14/21 × 3/2 = 42/42 = 1 х = 1.