Write the equation of the line through (4, -3) and vertical

If it is just a straight up and down vertical line, then the equation is x = 4

To find slope, you can use your two points in ysub1-ysub2/xsub1-xsub2

(2,60) and (6,120) are your points

120-60 60
———— = ——— = 15
6-2 4

Therefore, your slope is 15 or 15/1

This means the money earned increases by $15 for each hour worked

Hope this helps! :)