Textbook Problem

Write an equation for

a) the line through $\left(2, 3\right)$ and $\left(-3, 6\right)$.

b) the line through $\left(-2, -1\right)$ and parallel to the line through $\left(6, -3\right)$ and $\left(8, -9\right)$.

c) the line through $\left(3, -2\right)$ and perpendicular to the line $x+2y=4$.

d) the line through $\left(-3, 5\right)$ and parallel to the $x$-axis.