The power of the point $(-3, 7)$ with respect to a circle,with centre $(3, 7)$ and radius $2$,is

Find the equation of a circle that touches the lines $x = 0$,$y = 0$,and $x = 2c$.

$A$ circle touches both axes and its center lies in the fourth quadrant. If its radius is $1$,then its equation is:

The equation of the circle with centre $(2, -3)$ and touching the $X$-axis is

If the lines $3x - 4y - 7 = 0$ and $2x - 3y - 5 = 0$ are diameters of a circle with an area of $49\pi$ square units,then the equation of the circle is:

If the equation of the circle passing through the points $(-1,0), (-1,1), (1,1)$ is $ax^2+ay^2+2gx+2fy-2=0$,then $a=$