The given image of the circle is:

We know that the general equation of the circle is given by:

x² + y² + 2gx + 2fy + c = 0

Also,

Radius r =

Now,

r = 4 units.

We need to the find the equation of the circle which is concentric to the given circle and touches y-axis.

The centre of the circle remains the same.

Now, y-axis will be tangent to the circle.

Point of contact will be (0, 3)

Therefore, radius = 2

Now,

Equation of the circle:

(x – 2)² + (y – 3)² = (2)²

x² + 4 – 4x + y² + 9 – 6y = 4

x² + y² – 4x – 6y + 9 = 0