I’m pretty sure the equation is 28-f=n
and the answer is 2.
Very hard i think its 20.1
Answer:

Step-by-step explanation:
Mark any two point on the line
(-1 , 0) & (-3 , -1)
Slope = 
![= \frac{-1-0}{-3-[-1]}\\\\= \frac{-1}{-3+1}\\\\= \frac{-1}{-2}\\\\= \frac{1}{2}](https://tex.z-dn.net/?f=%3D%20%5Cfrac%7B-1-0%7D%7B-3-%5B-1%5D%7D%5C%5C%5C%5C%3D%20%5Cfrac%7B-1%7D%7B-3%2B1%7D%5C%5C%5C%5C%3D%20%5Cfrac%7B-1%7D%7B-2%7D%5C%5C%5C%5C%3D%20%5Cfrac%7B1%7D%7B2%7D)
m = 1/2 ; (-1 , 0)
Equation: 
![y - 0 = \frac{1}{2}(x - [-1])\\\\y = \frac{1}{2}(x + 1)\\\\y = \frac{1}{2}x + \frac{1}{2}](https://tex.z-dn.net/?f=y%20-%200%20%3D%20%5Cfrac%7B1%7D%7B2%7D%28x%20-%20%5B-1%5D%29%5C%5C%5C%5Cy%20%3D%20%5Cfrac%7B1%7D%7B2%7D%28x%20%2B%201%29%5C%5C%5C%5Cy%20%3D%20%5Cfrac%7B1%7D%7B2%7Dx%20%2B%20%5Cfrac%7B1%7D%7B2%7D)
i believe this is the answer n(2)-7<span />
63/9 + 40 - 35/7 =
7 + 40 - 5 =
47 - 5 =
42 <==