Stuck on this question

Question

In 1994, the moose population in a park was measured to be 4300. By 1996, the population was measured again to be 1200. If the population continues to change linearly:

Find a formula for the moose population, P, in terms of t, the years since 1990.

What does your model predict the moose population to be in 2004?

Answer 1

population dropped 4300-1200 = 3100 in 2 years.

that's 3100/2 =1550 less each year

in 1996 it's1200

in 1997 it's zero

in 2004 it's still zero

P=-1550t + 4300+2(3100) where t = number of years since 1990

P=-1550t + 10500

2004-1990 = 14

P(14) = -1550(14) +10500

= -21700 +10500

=-11200 = negative 11,200 moose in the year 2004

if somehow a negative number made any sense