The combined equation of the diagonals of the square formed by the pairs of lines $xy+6y-4x-24=0$ and $xy+6x-4y-24=0$ is

If the sides of a triangle $ABC$ are $2x^2-y^2=0$ and $x+y-1=0$,and the sides of another triangle $PQR$ are $2x^2-5xy+2y^2=0$ and $7x-2y-12=0$,then the distance between the centroid of $\triangle ABC$ and the orthocentre of $\triangle PQR$ is

If the lines represented by $a x^2+2 h x y+b y^2+2 g x+2 f y+c=0$ intersect on the $x$-axis,which of the following is in general incorrect?

If $(a, b)$ is the centroid of the triangle formed by the lines $4x^2 - 17xy + 4y^2 = 0$ and $x + y - 5 = 0$,and $c$ is the numerical value of the area of the triangle,then $a + b + c =$

The numbers $\alpha$ and $\beta$ are such that one of the lines of $2x^2 + \alpha xy + 3y^2 = 0$ coincides with one of the lines of $2x^2 + \beta xy - 3y^2 = 0$. If the two lines other than that common line are perpendicular,then $|\alpha + \beta|$ is equal to

For an integer $k$,if the area of the triangle formed by the pair of lines $S = 3x^2 - 2kxy + y^2 = 0$ with the line $L = 2x - y - 6 = 0$ is $36$ sq. units,then for the angle $\theta$ between the lines $S = 0$,$\sin \theta =$