a)
3 . ( 10 . x ) = 111
3 . 10 . x = 111
30 . x = 111
x = \(\frac{37}{10}\)
b) 3 + ( 10 . x ) = 111
10 . x = 111 - 3
10 . x = 108
x = 108 : 10
x = 10.8
3. ( 10.x ) = 111
10.x = 111 : 3
10.x = 37
x = 37 : 10
x = 3,7
______________________
3 + ( 10.x ) = 111
10.x = 111 - 3
10.x = 108
x = 108 : 10
x = 10,8