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The equation of a circle is given by \(x^{2} + y^{2} - 4x - ...

The equation of a circle is given by x2+y24x2y3. Find the radius and the coordinates of its centre.

A.

3,(1,2)

B.

22,(2,1)

C.

22,(2,1)

D.

9,(2,1)

Correct answer is C

Equation of a circle with radius r and centre (a, b).

= (xa)2+(yb)2=r2

Expanding, we have

x22ax+a2+y22by+b2=r2

Comparing, with x2+y24x2y3=0

2a=4a=2

2b=2b=1

r2a2b2=3r2=3+22+12=8

r=22