Find the equation of the circle with radius 5, whose centre lies on x-axis and passing through the point (2, 3).

The centre of the circle lies on x-axis.
  Its co-ordinates can be supposed as (h, 0)
The circle passes through point A (2, 3) and has a radius 5.
                             CA = 5 
       
When h = 6, the centre of circle is  radius of circle = 5
∴  The equation of circle is: 
or   
When h = -2, the centre of circle is (-2, 0) and the radius is 5
∴ the equation of circle is: 
or        
or          
Hence, the equation of circle is: