# The center of a circle is at (-5, 1) and it has a radius of 9. What is the equation of the circle?

Oct 11, 2016

${\left(x - - 5\right)}^{2} + {\left(y - 1\right)}^{2} = {9}^{2}$

#### Explanation:

The standard form for the equation of a circle is:

${\left(x - h\right)}^{2} + {\left(y - k\right)}^{2} = {r}^{2}$

where $r$ is the radius and $\left(h , k\right)$ is the center point.

Substituting in the given values:

${\left(x - - 5\right)}^{2} + {\left(y - 1\right)}^{2} = {9}^{2}$

You can write - -5 as + 5 but I do not recommend it.