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. 0.8x = 4
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- 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 19
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. 6(x+1) = 4(2x-1)
Verified step by step guidance1
Start by rewriting the equation \$6^{x+1} = 4^{2x-1}$ and recognize that the bases 6 and 4 are different and cannot be easily rewritten as powers of the same base.
Take the natural logarithm (or log base 10) of both sides to use the logarithm power rule, which allows you to bring the exponents down: \(\ln(6^{x+1}) = \ln(4^{2x-1})\).
Apply the logarithm power rule: \((x+1) \ln(6) = (2x - 1) \ln(4)\).
Distribute the logarithms: \(x \ln(6) + \ln(6) = 2x \ln(4) - \ln(4)\).
Collect all terms involving \(x\) on one side and constants on the other side, then factor out \(x\): \(x \ln(6) - 2x \ln(4) = - \ln(4) - \ln(6)\), which simplifies to \(x (\ln(6) - 2 \ln(4)) = - (\ln(4) + \ln(6))\). Finally, solve for \(x\) by dividing both sides by \((\ln(6) - 2 \ln(4))\).
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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 position, such as 6^(x+1) = 4^(2x-1). Solving these requires understanding how to manipulate and equate expressions with different bases or exponents.
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Solving Exponential Equations Using Logs
Logarithms and Their Properties
Logarithms are the inverse operations of exponentials and are used to solve equations where the variable is an exponent. Applying logarithms allows us to rewrite the equation in a form that isolates the variable for easier solving.
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Change of Base Property
Approximating Irrational Solutions
Some exponential equations yield irrational solutions that cannot be expressed exactly as fractions. These solutions are approximated as decimals, often rounded to a specified place value, such as the nearest thousandth.
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Graph Hyperbolas at the Origin
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