Answer :

1st: Expand the bracket
3t-3=9+t
2nd: Add the 3 to get rid of it on the first side. Do this to both sides
3t=12+t
3rd: Take away the t on the left hand side and one on the right hand side to just be left with t's on one side and integers on the other side
2t=12
4th: Divide both sides by 2 to find 1t
t=6

Hope this helps!! :)

3(t-1)=9+t
3t-3=9+t
3t-t=3+9
2t=12 (divide both sides by 2)
t=6