Answer:
![f(x) = -6x +120](https://img.qammunity.org/2020/formulas/mathematics/middle-school/z20qzlzr3cxd1wi3ohbebi56l18rm2orwl.png)
Explanation:
Let's call y the number of patients treated each week
Let's call x the week number.
If the reduction in the number of patients each week is linear then the equation that models this situation will have the following form:
![y = mx + b](https://img.qammunity.org/2020/formulas/mathematics/high-school/fc4cgm6covys37zv2opmmp9ps4jxyjepvh.png)
Where m is the slope of the equation and b is the intercept with the x-axis.
If we know two points on the line then we can find the values of m and b.
We know that During week 5 of flu season, the clinic saw 90 patients, then we have the point:
(5, 90)
We know that In week 10 of flu season, the clinic saw 60 patients, then we have the point:
(10, 60).
Then we can find m and b using the followings formulas:
and
![b=y_1-mx_1](https://img.qammunity.org/2020/formulas/mathematics/middle-school/ib7n9tmvvowdpy91ec58m49l2tadbgkvzm.png)
In this case:
and
![(x_2, y_2) = (10, 60)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/7unwrqahymfi287g6wazqjl0sy6yruwi6j.png)
Then:
![m=(60-90)/(10-5)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/g5ec7gbidh8dmarqlatse62dsuvpuafkd5.png)
![m=-6](https://img.qammunity.org/2020/formulas/mathematics/high-school/2tbyltj13spn0j74w3chot8ft7o2f2ych8.png)
And
![b=90-(-6)(5)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/wlv3yuzkajd860xptpwgxyeboq9lx2na58.png)
![b=120](https://img.qammunity.org/2020/formulas/mathematics/middle-school/5p4buniwtqewhpxj4lsobh9j9j2vwfui6n.png)
Finally the function that shows the number of patients seen each week at the clinic is:
![f(x) = -6x +120](https://img.qammunity.org/2020/formulas/mathematics/middle-school/z20qzlzr3cxd1wi3ohbebi56l18rm2orwl.png)