The solution of quadratic function is 5 and-1. D On the image, it is easy to get that D (4 4,5 5) P is the moving point on AB, so the range of t is (-1, 5).

The equation of straight line AD is: y=x+ 1? The equation of BD is: y=-5x+25.

The area of triangle ABD is fixed, so when point M is on BD, it is a critical situation, so it is divided into four segments.

When 0 < t ≤ 19? / 1 1? Time: s = (t+1)/2;

19 when? / 1 1? ≤t≤2: s=(- 1 1 1？ / 10)? t^2+(2 19？ /5)? t-(35 1？ /5? );

When 2≤t≤4: s=- 1 1? / 10? t2+ 19？ /5? t+49？ / 10?

When 4≤t≤5: s=(5? /2)? t2-25t+ 125/？ 2? .