Answer:
13 means the starting number
13 is the y-intercept (0,13)
I think the correct answer from the choices listed above is option D. The equation that would satisfy all of the points plotted above would be y=-2x. From the plot, we can see that the y-intercept is equal to zero and by using two points we can calculate the slope to be equal to -2. Giving an equation which is y=-2x.
