Question

How do you find the equation of the circle given center at (2, -5) and has radius 3?

Answer 1

`x^2+y^2-4x+10y+20=0`

Explanation:

The equation of a circle that has center `(x_0,y_0)` and radius `r` is:

`(x-x_0)^2+(y-y_0)^2=r^2`

then let's substitute the given values:

`(x-2)^2+(y+5)^2=3^2`

or

`x^2+y^2-4x+10y+20=0`