How do you solve 2lnx+3ln2=52lnx+3ln2=5?

1 Answer
Dec 15, 2015

x ~= 4.30716x4.30716

Explanation:

Property of Logarithmic expression

log A + log B = Log(AB) " " " " " (1)logA+logB=log(AB) (1)
n log A= log A^n " " " " (2)nlogA=logAn (2)

Given :

2ln x + 3ln 2 = 52lnx+3ln2=5

Rewrite as:
Using rule (1)

lnx^2 + ln2^3 = 5lnx2+ln23=5

Using rule (1)

ln(x^2 * 8) = 5ln(x28)=5

Raise the expression to exponential form, with the base of ee

e^(ln(8x^2) = e^5eln(8x2)=e5

8x^2 = e^58x2=e5
x^2 = (e^5)/8x2=e58

x = +-sqrt((e^5)/8)x=±e58

x ~= 4.30716x4.30716

Because the argument of any logarithm always POSITIVE and greater than zero, due to domain restriction.