The correct option is D none of these
x2+xy−2y2−4x+7y−5=0⇒(x−y+1)(x+2y−5)=0
Intersection point is (1,2)
Equation of line passing through (1,2) and perpendicular to x−y+1=0 is
x+y−3=0
And equation of line passing through (1,2) and perpendicular to x+2y−5=0 is
2x−y=0
Hence their joint equation is
(x+y−3)(2x−y)=0