Show that the pairs of straight lines `2x^2+6x y+y^2=0` and `4x^2+18 x y+y^2=0` have the same set of angular bisector.

Show that the pairs of straight lines 2x^(2)+6xy+y^(2)=0 and 4x^(2)+18xy+y^(2)=0 have the same set of angular bisector.

Two straight lines x-3y-2=0 and 2x-6y-6=0

Two straight lines x - 3y - 2 = 0 and 2x - 6y - 6 =0

Angle between the pair of straight lines x^(2) - xy - 6y^(2) - 2x + 11y - 3 = 0 is

Show that the straight lines : x-y-1=0 , 4x+3y=25 and 2x-3y+1=0 are concurrent.

Show that the circles x^2 + y^2 - 2x-6y-12=0 and x^2 + y^2 + 6x+4y-6=0 cut each other orthogonally.