What is the equation of the directrix of the parabola $x^2 = -8y$?

Let $PQ$ be a focal chord of the parabola $y^2=36x$ of length $100$,making an acute angle with the positive $x$-axis. Let the ordinate of $P$ be positive and $M$ be the point on the line segment $PQ$ such that $PM:MQ=3:1$. Then which of the following points does $NOT$ lie on the line passing through $M$ and perpendicular to the line $PQ$?

Let $M$ be the foot of the perpendicular from a point $P$ on the parabola $y^2=8(x-3)$ onto its directrix and let $S$ be the focus of the parabola. If $\triangle SPM$ is an equilateral triangle,then $P$ is equal to

Find the equation of the tangent at the vertex of the parabola $4y^2 + 6x = 8y + 7$.

The equation of the parabola whose vertex and focus lie on the $x$-axis at distances $a$ and $a'$ from the origin,respectively,is

The sum of squares of all possible values of $k$,for which the area of the region bounded by the parabolas $2y^2 = kx$ and $ky^2 = 2(y - x)$ is maximum,is equal to: