[填空题]
A study records the number o 5pv9o 8aze80)q88p ikxv9nb4o 3rs bw3sliuef chickens and ducks on a farm after t years, sta,q2k.1ai qst*qhi5 b urting on 1 January,q2i* usq,ik1 a5h.bqt 1997.Let c be the number of chickens on the farm after t years. The following table shows the number of chickens after t years.
The relationship between the variables can be modelled by the regression equation c=a t+b , where a and b are constants.
1. Find the value of a and the value of b . a ≈ b≈
2. Use the regression equation to estimate the number of chickens on the farm when t=6 .
Let d be the number of ducks on the farm after t years. The number of ducks can be modelled by the equation $d=400 e^{-k t}$ , where k is a constant.≈
3. Find the number of ducks on the farm on 1 January, 1997.
4. After six years, there are 377 ducks on the farm. Find the value of k .≈
5. Find the year during which the number of chickens and ducks were the same.
