What is the equation of a circle whose center is at (2,-4) and has a radius of 5 units?

Answer:
[tex](x - 2)^2 + (y +4)^2 = 25[/tex]
Step-by-step explanation:
Given
[tex](h,k) = (2,-4)[/tex] --- center
[tex]r = 5[/tex] --- radius
Required
Determine the equation
The equation of the circle is:
[tex](x -h)^2 + (y - k)^2 = r^2[/tex]
From the given parameters, we have:
[tex]h = 2[/tex]
[tex]k = -4[/tex]
[tex]r = 5[/tex]
So:
[tex](x -h)^2 + (y - k)^2 = r^2[/tex]
[tex](x - 2)^2 + (y --4)^2 = 5^2[/tex]
Express -- as +
[tex](x - 2)^2 + (y +4)^2 = 5^2[/tex]
Evaluate the squares
[tex](x - 2)^2 + (y +4)^2 = 25[/tex]