Question 201773
.
The function f(x) gives the lake level over the passt year, with x measured in days and y, that is, the f(x) values, measured in inches above last year's mean height.
A. What it the real-world meaning of f(60) ?
B. What is the real-world meaning of f(x)=-3 ?
C. What is an interpretation of f(x)=f(150) ?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~



Tutor @Theo in  his post produced very long answers, which I even can not read (so wordy they are).
It is difficult to me to believe (~ to imagine) that somebody in the world will read so long writing.
In that follows I will give my short answers.



<pre>
A.  f(60)  is the level in  the lake on the 60-th day;

      or, in more precise terms, f(60) tells us that on the 60-th day the water level in the lake
                                 was f(60) inches above or below the last year average water level 
                                 (depending on the sign of f(60): if f(60) >= 0,    then above,
                                                                  and if f(60) < 0, then below).


B.  f(x) = -3  means that on the day 'x' the water level in the lake was 3 inches below the last year average level.


C.  f(x) = f(150)  means that the water level in the lake on day  'x'  was the same as that of the 150-th day.
</pre>

Solved: all questions are answered.