6 Реши уравнения с комментированием и сделай проверку: a) (900 - x : 6) . 5 = 4200 б) 325 + (90 – n) : 17 = 330

a) (900 - x : 6) ⋅ 5 = 4200

900 - x : 6 = 4200 : 5

900 - x : 6 = 840

x : 6 = 900 - 840

x : 6 = 60

x = 60 ⋅ 6

x = 360

Проверка:

(900 - 360 : 6) ⋅ 5 = 4200

(900 - 60) ⋅ 5 = 4200

840 ⋅ 5 = 4200

4200 = 4200

б) 325 + (90 – n) : 17 = 330

(90 – n) : 17 = 330 - 325

(90 – n) : 17 = 5

90 – n = 5 ⋅ 17

90 – n = 85

n = 90 - 85

n = 5

Проверка:

325 + (90 – 5) : 17 = 330

325 + 85 : 17 = 330

325 + 5 = 330

330 = 330