Using the following equation, find the center and radius of the circle. You must show all work and calculations to receive credit.

x^2 − 4x + y^2 + 8y = −4

centre = (- 2, 3), radius = 3

Step-by-step explanation:

The equation of a circle in standard form is

(x - h)² + (y - k)² = r²

where (h, k) are the coordinates of the centre and r is the radius

To obtain this form use the method of completing the square on both the x and y terms.

x² + 2(2)x + 2² + y² + 2(- 3)y + (- 3)² = - 4 + 2² + (- 3)²

(x + 2)² + (y - 3)² = 9 ← in standard form

centre = (h, k) = (- 2, 3) and radius = \sqrt{9} = 3

idn

step-by-step explanation: