Let x be a time in hours and y be an amount of remaining entries. You have that:
- At start Ariel wants to write 8 entries for her blog. This means that x=0 and y=8 (0 entries were written). The point with coordinates (0,8) belongs to needed graph.
- After 2 hours, she has 5 entries left. This gives you that at x=2, y=5 and graph passes through the point (2,5).
- After 4 hours, she has 2 entries left. This gives you that at x=4, y=2 and graph passes through the point (4,2).
Find the slope of the line that is passing through the points
and
by formula

Thus, the slope is

Answer: graph of line going through (0, 8) with a slope of -1.5