The equation of a circle passing through (1, 1) and points of intersection of x2+y2+13x−3y=0 and 2x2+2y2+4x−7y−25=0 is
The equation of the required circle is
x2+y2+13x−3y+λx2+y2+2x−72y−252=0
This passes through (1, 1).
∴ 12+λ(−12)=0⇒λ=1.
Hence, the required circle is
x2+y2+13x−3y+x2+y2+2x−72y−252=0⇒4x2+4y2+30x−13y−25=0