Find the equation of the circle passing through the centre of the circle `x^2 + y^2 + 8x + 10 y - 7 =0` and concentric with the circle `x^2 + y^2 - 4x - 6y = 0`.

(i) Find the equation of a circle , which is concentric with the circle x^(2) + y^(2) - 6x + 12y + 15 = 0 and of double its radius. (ii) Find the equation of a circle , which is concentric with the circle x^(2) + y^(2) - 2x - 4y + 1 = 0 and whose radius is 5. (iii) Find the equation of the cricle concentric with x^(2) + y^(2) - 4x - 6y - 3 = 0 and which touches the y-axis. (iv) find the equation of a circle passing through the centre of the circle x^(2) + y^(2) + 8x + 10y - 7 = 0 and concentric with the circle 2x^(2) + 2y^(2) - 8x - 12y - 9 = 0 . (v) Find the equation of the circle concentric with the circle x^(2) + y^(2) + 4x - 8y - 6 = 0 and having radius double of its radius.

Find the equation of a circle passing through the centre of the circle x^2 + y^2+ 8x +10y-7=0 and concentric with the circle 2x^2 + 2y^2-8x-12y-9=0 .

Find the equation of the circle which passes through the centre of the circle x^2 + y^2 + 8x + 10y-7 = 0 and is concentric with the circle 2x^2 + 2y^2 - 8x - 12y - 9=0

Find the equation of the circle passing through the centre of the circle x^(2)+y^(2)+8x+10y-7=0 and concentric with the circle x^(2)+y^(2)-4x-6y=0

Find the equation of the circle passing through the centre of the circle x^2 +y^2 -4x-6y=8 and being concentric with the circle x^2 +y^2 - 2x-8y=5 .

Find the equation of the circle which passes through the centre of the circle x^(2)+y^(2)+8x+10y-7=0 and is concentric with the circle 2x^(2)+2y^(2)-8x-12y-9=0

Equation of circle passing through the centre of the circle x^2+y^2-4x-6y-8=0 and being concentric with the circle x^2+y^2-2x-8y-5=0 is

Equation of circle passing through the centre of the circle x^2+y^2-4x-6y-8=0 and being concentric with the circle x^2+y^2-2x-8y-5=0 is

Equation of circle passing through the centre of the circle x^2+y^2-4x-6y-8=0 and being concentric with the circle x^2+y^2-2x-8y-5=0 is

Equation of circle passing through the centre of the circle x^(2)+y^(2)-4x-6y-8=0 and being concentric with the circle x^(2)+y^(2)-2x-8y-5=0 is