Suppose that h(x+1) = h(x) +h(x-1) and that h(0) = 3 and h(1)= 12. find h(2), h(3) and h(-1)

For x=1
h(2)=h(1)+h(0)
h(2)=12+3
h(2)=15

for x=2
h(3)=h(2)+h(1)
h(3)=15+12
h(3)=27

for x=0
h(1)=h(0)+h(-1)
12=3+h(-1)
h(-1)=12-3
h(-1)=9

The answer is 225 miles per 4.5 hours. hope this ; )