there are three steps
1 rearrange the equation so "y" is on the left and everything else is on the right
2 plot the "y=" line (make it a solid line for y< or y> and a dashed line for y< or y>)
3 shade above the line for a "greater than" (y> or y>) line under that or below the line for a less than (y< or y< line under it)