Solve each equation. In Exercises 11–34, give irrational solutions as decimals correct to the nearest thousandth. In Exercises 35-40, give solutions in exact form. e3x-7 • e-2x = 4e
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 27
Textbook Question
Solve each equation. In Exercises 11–34, give irrational solutions as decimals correct to the nearest thousandth. In Exercises 35-40, give solutions in exact form. 0.05(1.15)x = 5
Verified step by step guidance1
Start with the given equation: \$0.05(1.15)^x = 5$.
Isolate the exponential expression by dividing both sides of the equation by 0.05: \((1.15)^x = \frac{5}{0.05}\).
Simplify the right side to get a numerical value: \((1.15)^x = 100\).
To solve for \(x\), take the logarithm of both sides. You can use the natural logarithm (ln) or common logarithm (log): \(\ln((1.15)^x) = \ln(100)\).
Use the logarithm power rule to bring down the exponent: \(x \cdot \ln(1.15) = \ln(100)\). Then solve for \(x\) by dividing both sides by \(\ln(1.15)\): \(x = \frac{\ln(100)}{\ln(1.15)}\).
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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 involves variables in the exponent, such as a^x = b. Solving these requires isolating the exponential expression and using logarithms to solve for the variable exponent.
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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 exponents. Applying log to both sides of an equation helps isolate the variable in the exponent, using properties like log(a^x) = x log(a).
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Change of Base Property
Rounding Decimal Answers
When solutions are irrational, they are often expressed as decimals rounded to a specified place value. Here, answers must be rounded to the nearest thousandth, meaning three digits after the decimal point.
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The Number e
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