Вынесите общий множитель за скобки:
а) 20 ⋅ 47 + 20 ⋅ 23
б) 57 ⋅ 81 − 39 ⋅ 81
в) 51 ⋅ 43 + 12 ⋅ 43
г) 38 ⋅ 39 − 38 ⋅ 20
Ответ
а) 20 ⋅ 47 + 20 ⋅ 23 = 20 ⋅ (47 + 23)
б) 57 ⋅ 81 − 39 ⋅ 81 = 81 ⋅ (57 − 39)
в) 51 ⋅ 43 + 12 ⋅ 43 = 43 ⋅ (51 + 12)
г) 38 ⋅ 39 − 38 ⋅ 20 = 38 ⋅ (39 − 20)