1)L2的解析式Y=4分之3(x+1)(X-4)
2)ABC是等腰三角形,因为C(0,-3)勾股定理得BC=5,又AB=5,所以是等腰
3)OC=3,PD=6.因D在LI上,P在L2上,两点的纵坐标之和为6即可求出点P(4/3,-14/3)