Given function f(x) which is described by "<span>Dawn writes 800 pages in 80 days".
From this function we can notice that Dawn writes 0 pages in 0 days, (i.e. the initial point of the function is point (0, 0).
Recall that the slope, m, of a line passing through points:
![(x_1,y_1)](https://tex.z-dn.net/?f=%28x_1%2Cy_1%29)
and
![(x_2,y_2)](https://tex.z-dn.net/?f=%28x_2%2Cy_2%29)
is given by
![m= \frac{y_2-y_1}{x_2-x_1}](https://tex.z-dn.net/?f=m%3D%20%5Cfrac%7By_2-y_1%7D%7Bx_2-x_1%7D%20)
Function f(x) passes through points (0, 0) and (80, 800).
Thus the slope of function f(x) is given by
![m= \frac{800-0}{80-0} = \frac{800}{80} =10](https://tex.z-dn.net/?f=m%3D%20%5Cfrac%7B800-0%7D%7B80-0%7D%20%3D%20%5Cfrac%7B800%7D%7B80%7D%20%3D10)
Give function g(x), passing through points (2, -6) and (4, 12), the slope is given by
![m= \frac{12-(-6)}{4-2} = \frac{12+6}{2} = \frac{18}{2} =9](https://tex.z-dn.net/?f=m%3D%20%5Cfrac%7B12-%28-6%29%7D%7B4-2%7D%20%3D%20%5Cfrac%7B12%2B6%7D%7B2%7D%20%3D%20%5Cfrac%7B18%7D%7B2%7D%20%3D9)
It can be seen that the slope of f(x) and the slope of g(x) are close.
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