Ответ:

Х × 7 = 330-274

X × 7 = 56

X = 56:7

X = 8

(502-2) × a = 1000

500 × a = 1000

a = 1000:500

a = 2

X + 30×5 = 365

X + 150 = 365

X = 365-150

X = 215

X : 4 = 100 - 22

X : 4 = 78

X = 78×4

X = 312

Ответ:

х•7=330-274

х•7=56

х=56:7

х=8

8•7=330-274