$y=3x+2$y=3x+2

$y=-3x+2$y=-3x+2

$\displaystyle y= \frac{1}{3}x+1$\displaystyle y= \frac{1}{3}x+1

$\displaystyle y=- \frac{1}{3}x+1$\displaystyle y=- \frac{1}{3}x+1