418. Решите уравнение: a) (x - 18,2) + 3,8 = 15,6; б) 34,2 - (17,9 – y) = 22; в) 16,5 - (t + 3,4) = 4,9; г) r + 16,23 - 15,8 = 7,1.

Решим уравнения: a) $$ (x - 18.2) + 3.8 = 15.6 $$ $$ x - 18.2 = 15.6 - 3.8 $$ $$ x - 18.2 = 11.8 $$ $$ x = 11.8 + 18.2 $$ $$ x = 30 $$ б) $$ 34.2 - (17.9 - y) = 22 $$ $$ 17.9 - y = 34.2 - 22 $$ $$ 17.9 - y = 12.2 $$ $$ y = 17.9 - 12.2 $$ $$ y = 5.7 $$ в) $$ 16.5 - (t + 3.4) = 4.9 $$ $$ t + 3.4 = 16.5 - 4.9 $$ $$ t + 3.4 = 11.6 $$ $$ t = 11.6 - 3.4 $$ $$ t = 8.2 $$ г) $$ r + 16.23 - 15.8 = 7.1 $$ $$ r + 0.43 = 7.1 $$ $$ r = 7.1 - 0.43 $$ $$ r = 6.67 $$ Ответ: a) x = 30; б) y = 5,7; в) t = 8,2; г) r = 6,67