The combined equation of the bisectors of the angles between the coordinate axes is:

The joint equation of the bisectors of the angles between the lines $x=5$ and $y=3$ is

The joint equation of the pair of lines passing through the point of intersection of the lines represented by $2x^{2}-xy-15y^{2}-7x+32y-9=0$ and parallel to the coordinate axes is:

If the pair of straight lines $xy - x - y + 1 = 0$ and the line $ax + 2y - 3 = 0$ are concurrent,then $a =$

If the real pair of lines $L_1 : ax^2 + 2hxy + by^2 = 0$ represents the angle bisectors of the real lines given by $L_2 : Ax^2 + Bxy + Cy^2 + Dx + Ey + F = 0$,then which of the following is incorrect?

The joint equation of the bisectors of the angles between the lines represented by $2x^2 + 11xy + 3y^2 = 0$ is: