Question

2. Find the centre and radius of circle x2+ y2 - 6x - 8y +9 =0

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Answer 1

Given the equation of the circle is x  

2

+y  

2

−6x−8y+24=0

or, (x  

2

−6x+9)+(y  

2

−8y+16)−1=0

or, (x−3)  

2

+(y−4)  

2

=1

So, the centre is (3,4) and radius is 1.

Answer 2

Answer:

C=(3,4); r=4

Step-by-step explanation:

General equation of circle X2+Y2-2gX-2fY+C=0

where -2g,-2f are centers of the circle

From given eguation

-2g=-6

g=3

-2f=-8

f=4

r=root of g2+f2-c

r=root of 3*3+4*4-9

r=root of 16

r=4