Suppose that I need to find the equation of the plane $P$ which contains a line $l(t)$, given parametrically as
$$ l(t) = \bigg(x(t), y(t), z(t) \bigg) = (v_1t + x_0, v_2t + y_0, v_3t + z_0). $$
The plane $P$ must also be perpendicular to another plane, whose equation is $Ax + By + Cz + D = 0$. Assuming that for given values of $v_1, v_2, v_3, x_0, y_0, z_0, A,B,C$ and $D$ this problem has a solution (a plane $P$ satisfying all of these required conditions), how would one go about starting to solve this problem?
The normal $N$ of your desired plane must be perpendicular to two vectors
Since it's perpendicular to these two vectors, $N$ must be parallel to their cross product.
Is that enough to get you started?