I. Find the center and radius of the following equations of a circle. Sketch the graph.

1. (x − 9)
2 + (y − 5)
2 = 16

2. (x − 3)
2 + (y + 3)
2 = 25

3. (x + 2)
2 + (y + 7)
2 = 36

II. Determine the standard form of equation of the following circles. Sketch the graph.

1. x
2 + y
2 − 2x − 8y + 4 = 0
2. x
2 + y
2 − 5x − 3y − 6 = 0