Easy. You need to solve for t. There are two ways you can do this:
1) Multiply both sides by -4.5. This will give you -10.8 on the left, and t by itself on the right.
OR
2) Multiply both sides by 4.5. You'll get 10.8 on the left and -t on the right. Then, divide both sides by -1 (tere's an invisible 1 in front of the t), to get -10.8=t.
Either way works, just depends on which way you're more comfortable with it.
