Consider the sum of the terms, ln(1/e)+ln(ab)
The function ln here is defined as a function that for whatever value you enter, you get the supposed number of times you're supposed to multiply the number e with itself.
In simple terms, ln(x) equals y, where y is such a number that when e*e*e*.....*e*e for y times (or in short e^y) gives back x to us.
Take note of the first term given in the sum. ln(1/e).
1/e can be re-written as e^-1
So, ln(1/e)=ln(e^-1)
Another important identity of ln function is that if we have a y=x^m, then ln(y)=ln(x^m)=mlnx AAm inRR
So, ln(e^-1)=-1*lne and if you remember what I typed up in the third paragraph, then you'll realize that lne=1, so ln(1/e)=-1
ln(ab) can't be simplified further than it is, so we'll have to keep it that way.
Replacing the term for ln(1/e) with what we've got, we come to the conclusion as written in the "answers" part.
