# How do you write the standard equation for the circle center (–6, 7), r = 9?

May 26, 2018

${\left(x + 6\right)}^{2} + {\left(y - 7\right)}^{2} = 81$

#### Explanation:

Standard equation for a circle is:

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

$r = r a \mathrm{di} u s = 9$

$\left(h , k\right) = \left(- 6 , 7\right)$ is the shift from $\left(0 , 0\right)$

${\left(x - \left(- 6\right)\right)}^{2} + {\left(y - 7\right)}^{2} = {9}^{2}$

${\left(x + 6\right)}^{2} + {\left(y - 7\right)}^{2} = 81$

graph{(x+6)^2 + (y - 7)^2 = 81 [-22.33, 17.67, -3.12, 16.88]}