# How do you find the center and radius of the circle given #3x^2+3y^2+12x-6y+9=0#?

##### 1 Answer

Nov 23, 2016

The center and radius are related to the coefficient of the equation.

#### Explanation:

First divide all the equation by three to put in simple form:

Now consider the general equation of the circle is:

where the center is the point

Expanding:

Comparing similar terms, you can easily see that:

graph{x^2+y^2+4x-2y+3=0 [-10.375, 9.625, -4.08, 5.92]}