It's already at the lowest term. It can't be simplified any farther.
When you reduce or simplify, you have to find a common number that both the numerator and denominator can be divide by. In this case there is no common number that can be divide into 2 and 9.
If you add 15 to both sides, you get h = 3.2t + 15. This is basically a slope-intercept equation, and simply from that, you can tell that the slope (the rate) is 3.2.
