How do you write the standard from of the equation of the circle given center C(-3, -1) and has a radius of 7?

Sep 19, 2016

${\left(x + 3\right)}^{2} + {\left(y + 1\right)}^{2} = 49$

Explanation:

The standard form of the equation of a circle is.

$\textcolor{red}{\overline{\underline{| \textcolor{w h i t e}{\frac{a}{a}} \textcolor{b l a c k}{{\left(x - a\right)}^{2} + {\left(y - b\right)}^{2} = {r}^{2}} \textcolor{w h i t e}{\frac{a}{a}} |}}}$
where (a ,b) are the coordinates of the centre and r, the radius.

here a = - 3 , b = - 1 and r = 7

substitute these values into the standard equation.

${\left(x - \left(- 3\right)\right)}^{2} + {\left(y - \left(- 1\right)\right)}^{2} = {7}^{2}$

$\Rightarrow {\left(x + 3\right)}^{2} + {\left(y + 1\right)}^{2} = 49 \text{ is the equation}$