Find the center and radius of x2 plus y2-6x plus 4y equals -4?

Answer 1

Given:

x2 + y2 - 6x + 4y = -4

We'll start by rearranging for clarity:

x2 - 6x + y2 + 4y + 4= 0

We can already get a perfect square with our y-value, so let's do that

x2 - 6x + (y + 2)2 = 0

Now to get x down to one term, you need to complete the square:

x2 - 6x + 9 + (y + 2)2 = 9

(x - 3)2 + (y + 2)2 = 32

And that gives you the answer. The circle has a center point of (3, -2), and a radius of 3.