The triangle formed by the lines $2 x^2+x y-6 y^2=0$ and $x+y-1=0$ is

If $A(1,0), B(0,-2)$ and $C(2,-1)$ are three fixed points, then the equation of the locus of a point $P$ such that area of $\triangle P A B$ is equal to area of $\triangle P A C$ is

The transformed equation of $3 x^2-4 x y=r^2$ when the coordinate axes are rotated about the origin through an angle of $\tan ^{-1}(2)$ in positive direction is