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35 votes
35 votes
I’m doing this assignment called solving logarithmic equations and got stuck on this question

I’m doing this assignment called solving logarithmic equations and got stuck on this-example-1
User Frankclaassens
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1 Answer

11 votes
11 votes

Here are the steps in solving the value of x in the equation.

1. Subtract 4 on both sides of the equation.


\begin{gathered} 4+(9\text{ }ln\text{ }x)-4=15.8-4 \\ 9\text{ }ln\text{ }x=11.8 \end{gathered}

2. Divide both sides of the equation by 9.


\frac{9\text{ }ln\text{ }x}{9}=(11.8)/(9)\Rightarrow ln\text{ }x=1.31111

3. By definition of natural logarithm:


ln\text{ }x=y\Leftrightarrow e^y=x

We can rewrite ln x = 1.3111 as:


e^(1.31111)=3.71

Therefore, the value of x is 3.71. (Option D).

User Adam Arold
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