Step-by-step explanation:
A)
We know that the water level is decreasing by 25 ft per day. This means that -25x would be the first part of the equation.
We also know that the water level starts at 45 ft when x=0.
Given this information, we can create an equation as follows
[tex]f(x)=-25x+45[/tex]
B)
Now that we have our equation, we can plug in 10 for x in order to find the height of the river
[tex]f(10)=-25(10)+45\\\\f(10)=-250+45\\\\f(10)=-205[/tex]
This means that after 10 days, the height of the river is -205 ft.
