3. Реши уравнения: а) 474 - y : 3 = 293 б) (10 - x) × 21 = 588 в) 650 + 9 × a = 1100 г) (x - 28) : 31 = 16

а) 474 - y : 3 = 293

y : 3 = 474 - 293

y : 3 = 181

y = 181 × 3

y = 543

б) (10 - x) × 21 = 588

10 - x = 588 : 21

10 - x = 28

x = 10 - 28

x = -18

в) 650 + 9 × a = 1100

9 × a = 1100 - 650

9 × a = 450

a = 450 : 9

a = 50

г) (x - 28) : 31 = 16

x - 28 = 16 × 31

x - 28 = 496

x = 496 + 28

x = 524