# Logarithms 15 - Solving Equations

Taught by YourMathGal
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Part of video series
Meets NCTM Standards:
Lesson Summary:

In this lesson on logarithms, the speaker shows how to solve equations with variables in the exponent using logs. The video covers five example problems, and the speaker walks through the steps of solving each one. The lesson uses both natural logs and log base 10, and the speaker also offers tips on checking solutions and approximating answers to four decimal places.

Lesson Description:

Uses change of base to solve equations with the variable in the exponent. .

More free YouTube videos by Julie Harland are organized at http://yourmathgal.com

• How do you solve equations when the variable is in the exponent?
• How can you use logarithms and the change of base formula to solve equations?
• How do you solve 4^x = 8 by making the bases the same?
• How do you solve 4^x = 80 using logarithms and the change of base formula?
• How do you solve 5^2x = 35?
• How do you solve e^x = 20?
• How do you solve 10^(2x - 3) = 48?
• How can you check your solution to equations where the variable is in the exponent?
• #### Staff Review

• Currently 4.0/5 Stars.
This lesson uses the change of base formula that was discussed in the previous lesson to solve equations where the variable is in the exponent. All steps are shown and explained in this video. The process for solving is moving the variable exponent down to the front of the expression by taking the log of both sides, and then solving by getting the variable by itself. This process is very important for future math problems you will encounter.