a) $y=35x+50$ b)Please see the graph. c) You can't have a negative number of hours for repairs, so that's why the graph should only be in quadrant I.
Work Step by Step
a) 50 for diagnosis, 35 per hour for repairs y=35x+50 b) The line on the graph goes through the points (0,50) and (1,85). The slope of the line is 35, and the y-intercept is 50. Thus, the line does go through points (0,50) and (1,85).