You can put this solution on YOUR website! 7(t-3) = 2(t-9)+2t
7t - 21 = 2t - 18 + 2t
7t - 21 = 4t - 18
7t - 4t = -18 + 21
3t = 3
t = 3/3
t = 1
To check, replace every t with 1 in your original linear equation.
If you get the same answer on both sides, you'll then know that t = 1 is correct.