Coordinates of the centre of the circle which bisects the circumferences of the circles x2+y2=1: x2+y2+2x−3=0 and x2+y2+2y−3=0 is:
The circle x2+y2−6x−4y+9=0 bisects the circumference of the circle x2+y2−(λ+4)x−(λ+2)y+(5λ+3)=0 if λ is equal to