Given that the radii of two circles are 5 and 8 respectively, and the center distance is 3, the positional relationship between the two circles is inscribed.

Reason: 8-5=3

That is: d=R-r, so the two circles are inscribed.

Given that the diameter of the circle O is 8, p is a point on the straight line L, and op=4, the positional relationship between the straight line L and the circle O is tangent or intersecting.

Reason: If the diameter is 8 and the radius is 4.

When OP is perpendicular to l, d = r, so the straight line l is tangent to the circle o,

When OP is not perpendicular to l, it intersects.