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. 70.3x=813
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 43
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. e2x−3ex+2=0
Verified step by step guidance1
Recognize that the equation \(e^{2x} - 3e^{x} + 2 = 0\) is an exponential equation that can be transformed into a quadratic form by substituting \(u = e^{x}\).
Rewrite the equation in terms of \(u\): since \(e^{2x} = (e^{x})^2\), the equation becomes \(u^2 - 3u + 2 = 0\).
Solve the quadratic equation \(u^2 - 3u + 2 = 0\) by factoring or using the quadratic formula to find the values of \(u\).
After finding the solutions for \(u\), substitute back \(u = e^{x}\) and solve for \(x\) by taking the natural logarithm: \(x = \ln(u)\).
Express the solution set in terms of natural logarithms and then use a calculator to approximate the decimal values of \(x\) 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
Exponential equations involve variables in the exponent, such as e^(2x). Solving these requires rewriting the equation to isolate the exponential term or substituting to form a quadratic equation, enabling the use of algebraic methods to find the variable.
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Solving Exponential Equations Using Logs
Logarithms and Their Properties
Logarithms are the inverse operations of exponentials, allowing us to solve for variables in exponents. Natural logarithms (ln) use base e, while common logarithms use base 10. Applying logarithms helps isolate the variable after rewriting the equation.
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Change of Base Property
Quadratic Equation Techniques
When an exponential equation can be rewritten as a quadratic form, techniques like factoring or the quadratic formula are used to find solutions. Recognizing this form simplifies solving complex exponential equations by treating e^x as a single variable.
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Introduction to Quadratic Equations
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