Answer:
![S(x)=42,000*(1.04)^(x)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/j4b6yri55pfebv0apzewyuemd3usiwtfjq.png)
Explanation:
We have as data
a = $42,000 (salary during the first year)
x = number of years
i = 4% = 0.04 (annual increase interest)
S(x) = Salary based on the years elapsed
"a" and "i" are constant for each year, while "x" increases one each year.
The function S(x) can be calculated like this:
![S(x)=a*(1+i)^(x)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/pwkdn381k2rm74oztjmx4qu975w6ik14zz.png)
Substituting constant values, we have
![S(x)=42,000*(1+0.04)^(x)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/e49tervgfq2hza6pwg1988kruqye12v7hz.png)
Simplifying, we have
![S(x)=42,000*(1.04)^(x)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/j4b6yri55pfebv0apzewyuemd3usiwtfjq.png)
Hope this helps!