Answer :
Subtract 4 from both sides
3x= 31-4
3x= 27
Divide both sides by 3 so x will be by itself. 27 divided by 3 is 9 so x=9
3x= 31-4
3x= 27
Divide both sides by 3 so x will be by itself. 27 divided by 3 is 9 so x=9