Let P(x, y) = x2 + y2 - 10x - 6y - 3
P(2, -1) = 4 + 1 - 20 + 6 - 3 = 11 - 23 = -12 < 0
P(3, 2) = 9 + 4 - 30 - 12 - 3 = 13 - 45 = -32 < 0
P(3, 8) = 9 + 64 - 30 - 48 - 3 = 73 - 81 = -8 < 0
Hence, point (2, -1), (3, 2) & (3, 8) will lie inside the circle. Therefore triangle which made by vertices (2, -1), (3, 2) & (3, 8) will completely lie inside the given circle.