SOLUTION: 8. ln (e5) A. 4 B. 5 C. 2 D. 0 E. 3 F. 1 9. ln (-5) A. 1 B. 2 C. 0 D. no solution E. 4 F. 3

Algebra ->  Exponential-and-logarithmic-functions -> SOLUTION: 8. ln (e5) A. 4 B. 5 C. 2 D. 0 E. 3 F. 1 9. ln (-5) A. 1 B. 2 C. 0 D. no solution E. 4 F. 3      Log On


   

Question 1199060: 8. ln (e5)
A. 4
B. 5
C. 2
D. 0
E. 3
F. 1

9. ln (-5)
A. 1
B. 2
C. 0
D. no solution
E. 4
F. 3
Found 2 solutions by ikleyn, math_tutor2020:
Answer by ikleyn(52800) About Me  (Show Source):
You can put this solution on YOUR website!
.

(A)  ln%28e%5E5%29 = 5.    ANSWER



(B)  ln%28-5%29%29  does not exist, since the logarithm function is not defined for negative values of its argument.



Answer by math_tutor2020(3817) About Me  (Show Source):
You can put this solution on YOUR website!

Logs and exponential functions of the same base cancel each other out.
Ln(e^x) = x

Therefore,
Ln(e^5) = 5

The natural log function has a domain of x > 0
Meaning that Ln(-5) leads to "no solution".

The reasoning is that y = e^x is entirely above the x axis for all real numbers x. It's impossible to have y be negative (unless you involve complex numbers in the form a+bi)