I need some help with these two questions, does anyone know where to start?

Show that the points in R^3 equidistant from two fixed points p and q form a

plane, and find its equation.

Let p + tv, t in R be the parametric description of a line l and let q be a point

not on l. Show that the points (in R^3) which lie on a line through p + tv and q

(some variable t) make up a plane. What is its equation?