How do you find the center and radius for x^2 + (y + 6)^2 = 49 ?

1 Answer
Sep 10, 2016

centre = (0 ,-6) , radius = 7

Explanation:

The standard form of the equation of a circle is.

color(red)(bar(ul(|color(white)(a/a)color(black)((x-a)^2+(y-b)^2=r^2)color(white)(a/a)|)))
where (a ,b) are the coordinates of the centre and r, the radius.

x^2+(y+6)^2=49" is in this form."

That is (x-0)^2+(y-(-6))^2=7^2

and by comparison with the standard form.

a=0,b=-6" and " r=7

Thus, centre = (0 ,-6) and radius = 7