Answer to Question #57676 in Analytic Geometry for sanjiv

Question

Find the equation of the circle determined by the given conditions:
10. tangent to the x-axis and passing through (5, 1) and (12, 8)
11. tangent to the line y= -1 and containing the points (1, 1) and (3, 3)
12. tangent to the lines 2x + y = 4, 2x + y =2 and x - 2y + 5 = 0
13. passing through the origin and tangent to the lines 3x + 4y - 10 = 0 and 4x + 3y - 5 = 0
14. inscribed in a triangle with sides on the lines x - 3y = -5, 3x + y = 1 and 3x - y = -11
15. inscribed in a triangle whose vertices are (0, 6), (8, 6), and (0, 0)
16. having radius of square root of 5, through (0, 4) and (3, 7).
17. radius and tangent to the line 2x + y -1 = 0 at (1, -1)
18. tangent to 3x - 2y - 9 = 0 and 2x - 3y - 1 = 0 and center on 2x + y - 10 = 0