Write the equation of a circle with a center (-9,0) and radius 2√5

(x + 9) ² + y² = 20

Step-by-step explanation:

The standard equation of a circle is (x - h) ² + (y - k) ² = r², where the center is (h, k) and r is the radius. By plugging in the given numbers from the question, we have [ x - (-9) ]² + (y - 0) ² = (2√5) ².

(x + 9) ² + y² = (2) (√5) (2) (√5)

(2) (2) = 4 (√5) (√5) = 5 (4) (5) = 20

(x + 9) ² + y² = 20