Use natural logarithms to solve the equation. 8e3x + 9 = 13.

Question

I am really confused how to solve this, and how to put it into a calculator.

 

A)0.337

B)-2.838

C)0.058

D)-0.231

Answer 1

Hello Brooklyn,

If I can assume the (3x) is the exponent, i.e. 8e^3x+9=13, then

 

8e^3x = 4, by subtracting 9 from both side,

 

e^3x = .5, by dividing both sides by 8,

 

log_e(.5) = 3x, using the definition of log,

 

ln(.5) = 3x, since log_e means ln

 

x = (ln(.5))/3, by dividing both sides by 3,

 

which is approximately answer (D)