Question

(x+8)^2+(y-4)^2=81
whats the center and the radius? im confused on how to do this
any help I will fan and medal

Answer 1

actually the equation of a circle is\[x ^{2}+y ^{2}=a ^{2}\]

Answer 2

u hv to compare ur given equation with my equation

Answer 3

obviously \[a ^{2}=81\]

Answer 4

\[a=9\]

Answer 5

a=radius of a circle

Answer 6

the center and radius eq of the circle is \[ (x – h)^2 + (y – k)^2 = r^2\]

with the center being at point (h,k) and the radius being r

Answer 7

and in my equation the center will b (0,0)

Answer 8

so the center will b\[x+8=0\]

Answer 9

\[x=-8\]

Answer 10

so what would be the center and radius in your problem @kittykat96?

Answer 11

and\[y-4=0\]

Answer 12

\[y=4\]

Answer 13

actually the equation of a circle with center \((h,k)\) and radius \(r\) is
\[(x-h)^2+(y-k)^2=r^2\]

Answer 14

so center is (-8,4)

Answer 15

yup i wrote that but may have worded it wrong @satellite73

Answer 16

ok so the center is (-8,4) and the radius is 9? im really confused right now so many people trying to answer at once lol but I think I got it

Answer 17

yup that is the answer but use the formula @satellite73 and i put up when you want to solve for the center and radius r

Answer 18

yes, you have it

Answer 19

ok thank you guys