The circumcentre of the triangle formed by the lines x+y−1=0, x−y−1=0, x−3y+3=0 is

x+y−1=0 --------(1)x−y−1=0 --------(2)x−3y+3=0 --------(3)Solving (1),(3) C=(0,  1) Solving (2), (3) B=(3,  2) Circum centre = midpoint of BC=(32,32)