1) 4(9+7x) + 21 = 393
36 + 28x + 21 = 393
28x + 57 = 393
28x = 393 - 57
28n = 336
n = 336/28
n = 12
1)393-21=4(9+7x)
2)372:4=(9+7x)
3)93-9=7x
4)84:7
x=12
1) 4(9+7x) + 21 = 393
36 + 28x + 21 = 393
28x + 57 = 393
28x = 393 - 57
28n = 336
n = 336/28
n = 12
1)393-21=4(9+7x)
2)372:4=(9+7x)
3)93-9=7x
4)84:7
x=12