Question

уравнения 4•(9+7х)+21=393

Answer 1

4*(9+7х)+21=393
36+28х+21=393
57+28х=393
28х=393-57
28х=336
х=336:28
х=12

Answer 2

4*(9+7x)+21=393
4*(9+7x)=393-21
4*(9+7x)=372
9+7x=372:4
9+7x=93
7x=93-9
7x=84
x=84:7
x=12