1. Вычислите: a) 0.8 √225 − 0.5 √1.21; b) 2 − 3 √[25/36]; c) (0.5 √20)^2.

a) 0.8 √225 − 0.5 √1.21 = 0.8 * 15 − 0.5 * 1.1 = 12 − 0.55 = 11.45. b) 2 − 3 √[25/36] = 2 − 3 * 5/6 = 2 − 2.5 = −0.5. c) (0.5 √20)^2 = (0.5 * √20)^2 = (0.5 * √4 * √5)^2 = (0.5 * 2 * √5)^2 = (√5)^2 = 5.