Hello!
What you would need to do first is distribute the numbers inside the parenthesis.
6(t - 3) = 2(9 - 2t)
6t - 18 = 18 - 4t
Now that they've been distributed, you need to move all variables to one side, preferably to the left as it would make it easier to read and t would be positive.
6t - 18 = 18 - 4t
10t = 36
All that is left is to divide by 10 in order to leave t alone.
t = 3.6 or 18/5