Question

x^2 + y^2 - 8X + 12Y - 20 = 0 What the radius?

Answer 1

x^2-8x+y^2+12y=20
x^2-8x+(16)+y^2+12y+36=20+16+36
(x-4)^2+(y+6)^2=72
r^2=72
\[r= \sqrt{72}\approx8.4\]

Answer 2

thank you so much!

Answer 3

by complete the square for x & y.

Answer 4

did you use the equation (x-h)^2+(y-k)^2=r^2

Answer 5

yes