If one of the lines given by the equation $x^{2}+kxy+2y^{2}=0$ is $x+2y=0$,then $k=$

If the sum and product of the slopes of the lines represented by $4x^2 + 2hxy - 7y^2 = 0$ are equal,then $h = \dots$

For $l \in R$,the equation $(2 l-3) x^2+2 l x y-y^2=0$ represents a pair of lines

If the equation $7x^2 - 14xy + py^2 - 12x + qy - 4 = 0$ represents a pair of parallel lines,then the value of $\sqrt{p^2 + q^2 - pq}$ is

Which among the following represents the combined equation of a pair of lines passing through the point $(1, 0)$ and parallel to the lines represented by $2x^2 - xy - y^2 = 0$?

If the sum of the slopes of the lines represented by the equation $x^2 - 2xy \tan A - y^2 = 0$ is $4$,then $\angle A = $