Answer:
Step-by-step explanation:
You add the like-terms so the things that are the same, pretty much.
so 3t^2+7t^2 = 10t^2
and you can subtract 8t^2 from 10t^2 because they are like terms so you get 2t^2
then bring -5t down and subtract 9 from 6 and boom you're done