Solve each exponential equation in Exercises 1–22 by expressing each side as a power of the same base and then equating exponents. 8(x+3)=16(x−1)
Table of contents
- 0. Review of Algebra4h 18m
- 1. Equations & Inequalities3h 18m
- 2. Graphs of Equations1h 43m
- 3. Functions2h 17m
- 4. Polynomial Functions1h 44m
- 5. Rational Functions1h 23m
- 6. Exponential & Logarithmic Functions2h 28m
- 7. Systems of Equations & Matrices4h 5m
- 8. Conic Sections2h 23m
- 9. Sequences, Series, & Induction1h 22m
- 10. Combinatorics & Probability1h 45m
6. Exponential & Logarithmic Functions
Solving Exponential and Logarithmic Equations
Problem 23
Textbook Question
Solve each exponential equation in Exercises 23–48. Express the solution set in terms of natural logarithms or common logarithms. Then use a calculator to obtain a decimal approximation, correct to two decimal places, for the solution. 10x=3.91
Verified step by step guidance1
Identify the given exponential equation: \$10^{x} = 3.91$.
To solve for \(x\), take the logarithm of both sides. You can use either the common logarithm (base 10) or the natural logarithm (base \(e\)). For example, applying the common logarithm gives: \(\log(10^{x}) = \log(3.91)\).
Use the logarithmic identity \(\log(a^{b}) = b \log(a)\) to simplify the left side: \(x \log(10) = \log(3.91)\).
Since \(\log(10) = 1\), the equation simplifies to \(x = \log(3.91)\).
To find the decimal approximation, use a calculator to evaluate \(\log(3.91)\) and round the result to two decimal places.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Exponential Equations
An exponential equation is one in which the variable appears in the exponent, such as 10^x = 3.91. Solving these equations often requires rewriting or applying logarithms to isolate the variable and find its value.
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Logarithms and Their Properties
Logarithms are the inverse operations of exponentials, allowing us to solve for variables in exponents. Common logarithms (base 10) and natural logarithms (base e) are used to rewrite equations like 10^x = 3.91 as x = log(3.91) or x = ln(3.91)/ln(10).
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Change of Base Property
Using Calculators for Approximation
After expressing the solution in logarithmic form, calculators help find decimal approximations. This step involves evaluating logarithmic expressions and rounding the result to a specified precision, such as two decimal places.
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Solving Exponential Equations Using Logs
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