Question

Find the center and radius of the circle given by please help fast

Answer 1

Centre (4, -1)

Radius = 5

Explanation:

First, rearrange the equation, collecting x terms together and y terms together and any constants, move over to the other side, like so:

x² - 8x + y² + 2y = 8

Now, complete the square with both the x terms and y terms, like so:

(x - 4)² - 16 + (y + 1)² - 1 = 8

Move constants over to the other side;

(x - 4)² + (y + 1)² = 25

This is now the classical format of any circle equation and can be interpreted as such;

A circle with centre (4, -1) and radius 5