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Solve the doubts. There might be multiple solutions. There might be no solution

Solve the doubts. There might be multiple solutions. There might be no solution-example-1
User Nauman Ash
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1 Answer

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14 votes

11) You have the following equation:


\log _3(2x-7)=4

In order to determine if the equation has solution. Proceed as follow:

- Use the equation above as the exponent of 3:


3^(\log _3(2x-7))=3^4

- Then, by properties of the logarithms, you can cancel out the log_3:


3^(\log _3(2x-7))=2x-7=3^4

- Now, consider the second and third member of the previous equation:


2x-7=3^4

And solve for x by adding 7 both sides and then by dividing by 2 both sides:


\begin{gathered} 2x=3^4+7 \\ x=(3^4+7)/(2)=(81+7)/(2)=(88)/(2)=44 \end{gathered}

Hence, the solution for x = 44

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