What is the equation of a circle whose center is (2,0) and has a radius= 9?

The equation of a circle is: (x - h)² + (y - k)² = radius² where (h, k) is the center. Now just plug in your given information and simplify.

(x - 2)² + (y - 0)² = 9²

Your equation is:
(x - 2)² + y² = 81

(x-2)²+(y-0)²=9²
you need simplify it.
center(a,b) radius=R
(x-a)²+(y-b)²=R²

These are the multiples of 15 but what you are probably asking or what are the factors of 15