Question 114291
a) brain equation y=5.50x+15

Gregs equation y=6.25x+12

For the graph on the same grid for greg put the first pont on the y axis on 15 and increase 50.50 / hour and then draw a line 

for greg put the first point on 12 and then 6.25 increments / hour 

draw both lines and see when the line is at a same point (point of intersection) and when one is more than the other.