To evaluate a function, plug-in the values of the variables.
This notation means that the values of the variables are x=7, y=7 and x=7.
Plug-in these values to the function to get f(7,7,7).
Note that adding the term by itself is the same as multiplying the term by the number of times it is added.
Since `49e^7` is being added by itself three times, this can be express as:
Hence, `f(7,7,7)=147e^7` .
(For the second problem, kindly post it as separate question in Homework Help.)