Cvan you guys me plz i need to answer this rigth now x2 - 7 = 0

Acircle has a diameter will endpoints of (-2,8) and (6, 4). what is the center of the circle

Select the two pairs of figures that are similar.

1. if events a and b are non-overlapping events, how do you find the probability that one or the other occurs? 2. what does it mean if p(a or b) equals 1?