1. A point P(a,b) becomes (3,c) after reflection in x - axis, and (d,6) after reflection in the origin. Show that a = 3, b = - 6, c = 6, d = 2
2. If the pair of lines ax² + 2pxy - ay² = 0, bx² + 2qxy - by² = 0 are such that each pair bisects the angle between the other pair, then show that ab + pq = 0.
3. Find the equation of the circle concentric with the circle x2 + y2 - 8x + 6y - 5 = 0 and passes through the point (-2, -7)