Question

x
2
+ y
2
+ 6x − 8y + 8 = 0
represents a circle. Find its centre and show that its radius is
√
17.

Answer 1

center is (-3,4) and radius is \[\sqrt{17}\]

Answer 2

many thanks. please could you show me how you got this if possible

Answer 3

circle: (x-a)^2 +(y-b)^2=R^2
<=> x^2+y^2-2ax-2yb+a^2+b^2-R^2=0

Answer 4

with center (a,b) radius R

Answer 5

in case:
-2a=6 ->a=-3
-2b=-8 ->b=4
a^2+b^2-R^2=8 -> R=sqrt(17)

Answer 6

thank you that makes some sense. thank you for your help