Which of the following equations of a circle has center at
(1,-3) and radius of 5?
A. x² + y² = 25
B. (x-1)² + (y+3)² = 25
C. (x-1)² + (y-3)² = 25
D. (x+1)² + (y - 3)² = 25
The formula is (x-h)² + (y-k)² = r²
Be careful. The center coordinates are always subtracted from x and y. When you subtract a -3 it becomes a +3.