Question

-e^-3.9n-1 - 1 = -3

Answer 1

Without parentheses to tell me what is exponent and what is times what I do not have the slightest idea.

Answer 2

well, clearly the spacing indicates

-e^(-3.9n-1) -1 = -3
e^(-3.9n-1) = 2
-3.9n-1 = ln2
n = -(1+ln2)/3.9

Of course, I could be way off...