Question

What is the center and radius of the circle with the equation x2 + y2 – 8x + 4y – 61 = 0?

Answer 1

Center: (–4, –2); Radius = 9

Center: (–4, 2); Radius = 9

Center: (4, –2); Radius = 9

Center: (4, 2); Radius = 9

Answer 2

center is (-4,2) with radius 9

Answer 3

Thank you!

Answer 4

Welcome!

Answer 5

What is the general form of the equation of a circle with a center at the (4, 2) and a radius of 9?

Answer 6

(x – 4)2 + (y – 2)2 = 81

(x – 4)2 + (y + 2)2 = 81

(x + 4)2 + (y – 2)2 = 81

(x + 4)2 + (y + 2)2 = 81

Answer 7

If you dont mind :)

Answer 8

\[(x^2-8x)+(y^2-4y) = 61\]
\[(x^2-8x+16)+(y^2+4y+4) = 61+16+4\]
\[(x-4)^2 +(y+2)^2 = 9^2\]
general equation is \[(x+h)^2 +(y+k)^2 = r^2\]
with center (h,k) and radius r.