Different Forms of Equation of a Circle

If $(-3,2)$ lies on the circle $x^2+y^2+2gx+2fy+c=0,$ which is concentric with the circle $x^2+y^2+6x+8y-5=0,$ then $c$ is equal to

The centers of a set of circles, each of radius $3,$ lie on the circle $x^2+y^2=25.$ The locus of any point in the set is

The lines $2x-3y-5=0$ and $3x-4y=7$ are the diameters of a circle of area $154$ sq units, then the equation of the circle is

The locus of the centre of a circle, which touches externally the circle $x^2+y^2-6x-6y+14=0$ and also touches the $y$-axis, is given by the equation