Angles made by the lines represented by the equation $xy + y = 0$ with the $y$-axis are

If $m$ is the slope of one of the lines represented by $ax^{2}+2hxy+by^{2}=0$,then $(h+bm)^{2}$ is equal to

The square of the difference of the slopes of the lines represented by the equation $x^2(\sec^2 \theta - \sin^2 \theta) - 2xy \tan \theta + y^2 \sin^2 \theta = 0$ is:

If $p_1$ and $p_2$ denote the lengths of perpendiculars from $(2,3)$ onto the lines given by $15 x^2+31 x y+14 y^2=0$,and if $p_1 > p_2$,then $p_1^2 + \frac{1}{74} - p_2^2 + \frac{1}{13}$ is equal to

If $ax^2 - y^2 + 4x - y = 0$ represents a pair of lines,then $a = $

The straight lines represented by the equation $9x^{2}-12xy+4y^{2}=0$ are