-3/2k+b=0
b=3
The solution is k= 2 b=3.
The analytical formula of the straight line is y=2k+3.
OP=2OA=3, and the coordinate of point P is (-9/2,0) or (3,0).
s△ABP = 1/2xAPxOB = 1/2x3x 3 = 9/2