1, (1) Because every two straight lines determine an intersection point, each straight line has an intersection point with another (n- 1) straight lines, so * * has n(n- 1) intersections. However, each intersection point is calculated once, (for example,

(2) Similarly, * * has n(n- 1)/2 intersecting lines.

2.* * There are C8(4)+C8(6)=70+28=98 invitation methods.

Both students invited C8(4) and neither invited C8(6). Add them up.