12t +9
because you basically just take w of t and plug in 3t for t itself. This means you end up with 3(4t+3) and you evenly distribute, unless you want to simplify further you could maybe take it to 4t+3 but it just depends on the math youre doing. If you're taking calculus then you should be fine with the above answer since, you dont need to further simplify once you take the exam at the very end of your course. Hope this helps :)
