A few questions regarding Linear Equations.

Q1) "▲LMN has vertices L(-1,2) and M(-4,-1).

a) Find the coordinates of N such that ▲LMN is a right triangle.

b) Is there more than one solution? Explain."

So, basically, it's telling me to find the coordinates of N, and that one of the angles is 90 degrees/perpendicular.

Q2) "A and k are one-digit numbers. Given two lines,** Ax - 3y + 15 = 0** and **y = kx + 7**, determine the **values** of A and k if the two lines are:

a) parallel

b) perpendicular"

To be honest, I don't understand this question at all...