Question

Find the solution(s) of the logarithmic equation

ln(x+4)+ln(x−4)=0

Answer 1

use rules of logs

ln(x+4)+ln(x−4)=0 , x > 4
ln( (x+4)(x-4) ) = 0

e^0 = (x+4)(x-4)
1 =x^2 - 16
x^2 = 17
x = ±√17 , but x > 4

so x = √17