123. Примените распределительный закон умножения (раскройте скобки).

а) (a + 8) ⋅ 40 = a ⋅ 40 + 8 ⋅ 40 = 40a + 320; б) (12 − b) ⋅ 7 = 12 ⋅ 7 − b ⋅ 7 = 84 − 7b; в) 12 ⋅ (6 + с) = 12 ⋅ 6 + 12 ⋅ с = 72 + 12с; г) 10 − (d − 8) = 10 − d + 8 = 18 − d.