Hi, I don't know how to approach this question, thanks in advance! =)

Let

**v **be a unit vector and

**c** a real number, and let

**P** be the plane whose equation is

**r.v **=

** c** . Suppose also that

is a vector, and

**A** the point whose position vector relative to the origin is

.

a) Find in parametric vector form, the equation of the line

**l** that is perpendicular to

**P** and passes through

**A**.

b) Let

**B** be the point of intersection of the plane

**P** and the line

**l** in Part (a). Find a formula for the position vector of

**B** relative to the origin, in t erms of

,

**v** and

**c**.

=) yay