Для сравнения выражений необходимо вычислить их значения.
84 : (6 ⋅ 2) = 84 : 12 = 7
84 : 6 ⋅ 2 = 14 ⋅ 2 = 28
7 < 28
84 : (6 ⋅ 2) < 84 : 6 ⋅ 2
45 ⋅ 12 = 540
45 ⋅ 2 ⋅ 6 = 90 ⋅ 6 = 540
540 = 540
45 ⋅ 12 = 45 ⋅ 2 ⋅ 6
Ответ: 84 : (6 ⋅ 2) < 84 : 6 ⋅ 2; 45 ⋅ 12 = 45 ⋅ 2 ⋅ 6.