Chapter 4 - Writing Linear Functions - 4.3 - Writing Equations of Parallel and Perpendicular Lines - Exercises - Page 191: 3

Lines $a$ and $b$ have the same slope, so they are parallel.

Slope of line $a$ $=\frac{y_{2}-y_{1}}{x_{2}-x_{1}}=\frac{3-1}{0-(-3)}=\frac{2}{3}$ Slope of line $b$ $=\frac{2-0}{3-0}=\frac{2}{3}$ Slope of line $c$ $=\frac{0-(-3)}{3-(-2)}=\frac{3}{5}$ Lines $a$ and $b$ have the same slope, so they are parallel.