Answer:
The equation of the line of best fit is y = (-9/7)x + 13.
Explanation:
The y-intercept of this straight line is (0, 13); we could also say that b = 13.
Two points on the graph are (0, 13) and (7, 4). As we go from x = 0 to x = 7, x increases by 7; at the same time, y decreases by 9.
From this observation, we can easily calculate the slope of this line:
m = rise / run = -9/7.
Then the equation of the line of best fit is y = (-9/7)x + 13.