x^(2)+y^(2)+6x+8y+25=0" then find "x+y=?

If x^(2)+y^(2)-6x-8y=-25 , then find the values of x and y.

If the circle x^(2) +y^(2) -6x -8y+( 25-a^(2) ) =0 touches the axis of x, then a equals.

Find the length of the chord intercepted by the circle x^2+y^2-6x+8y-5=0 on the line 2x-y=5.

Find the radical centre of circles x^(2)+y^(2)+3x+2y+1=0,x^(2)+y^(2)-x+6y+5=0 and x^(2)+y^(2)+5x-8y+15=0 . Also find the equation of the circle cutting them orthogonally.

If the circles x^(2) + y^(2) - 6x - 8y + 12 = 0 , x^(2) + y^(2) - 4x + 6y + k = 0 cut orthogonally, then k =

The total number of common tangentss of x^(2)+y^(2) -6x-8y+9=0 and x^(2)+y^(2)=1 is

The equation x^(2)+y^(2)-6x+8y+25=0 represents