3. Упростите выражения.

a) 87a - 35a - 27a = (87 - 35 - 27) * a = 25a. b) 25 * m * 16 = (25 * 16) * m = 400m. c) 12c + 28 + 8c + 2 = (12c + 8c) + (28 + 2) = 20c + 30.