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. 5(2x+3)=3(x−1)
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- 0. Review of Algebra4h 18m
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- 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
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- 10. Combinatorics & Probability1h 45m
6. Exponential & Logarithmic Functions
Solving Exponential and Logarithmic Equations
Problem 45
Textbook Question
Solve each equation. Give solutions in exact form. log(2 - x) = 0.5
Verified step by step guidance1
Recall the definition of the logarithm: if \(\log_b A = C\), then \(A = b^C\). Here, the logarithm is base 10 (common logarithm), so rewrite the equation \(\log(2 - x) = 0.5\) as \$2 - x = 10^{0.5}$.
Express \$10^{0.5}\( as \)\sqrt{10}\( to keep the solution in exact form, so the equation becomes \)2 - x = \sqrt{10}$.
Isolate the variable \(x\) by subtracting \(\sqrt{10}\) from both sides: \$2 - \sqrt{10} = x$.
Rewrite the solution explicitly as \(x = 2 - \sqrt{10}\) to clearly state the exact form of the solution.
Check the solution by substituting \(x\) back into the original logarithmic expression to ensure the argument of the log, \$2 - x$, is positive, confirming the solution is valid.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Properties of Logarithms
Understanding the properties of logarithms is essential for solving log equations. For example, knowing that log_b(a) = c means b^c = a allows you to rewrite logarithmic equations in exponential form, which simplifies solving for the variable.
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Domain Restrictions of Logarithmic Functions
Logarithmic functions are only defined for positive arguments. This means the expression inside the log, such as (2 - x), must be greater than zero. Identifying and applying these domain restrictions ensures that solutions are valid.
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Solving Exponential Equations
After rewriting a logarithmic equation in exponential form, solving for the variable often involves isolating the variable in an exponential equation. This may require algebraic manipulation such as addition, subtraction, or division to find the exact solution.
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Solving Exponential Equations Using Logs
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