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. (1/2)x = 5
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 17
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. 4(x-1) = 32x
Verified step by step guidance1
Start with the given equation: \$4^{x-1} = 3^{2x}$.
Rewrite the bases as powers of prime factors if possible. Note that \$4\( can be written as \)2^2\(, so rewrite the equation as: \)\left(2^2\right)^{x-1} = 3^{2x}$.
Use the power of a power property: \(\left(a^m\right)^n = a^{mn}\), to simplify the left side: \$2^{2(x-1)} = 3^{2x}$.
Take the natural logarithm (or log base 10) of both sides to bring down the exponents: \(\ln\left(2^{2(x-1)}\right) = \ln\left(3^{2x}\right)\).
Apply the logarithm power rule: \(\ln(a^b) = b \ln(a)\), to get: \$2(x-1) \ln(2) = 2x \ln(3)\(. Then solve this linear equation for \)x\( by expanding and isolating \)x$.
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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 4^(x-1) = 3^(2x). Solving these requires understanding how to manipulate and equate expressions with different bases, often by applying logarithms or rewriting terms with common bases.
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Solving Exponential Equations Using Logs
Logarithms and Their Properties
Logarithms are the inverse operations of exponentials and are essential for solving equations where the variable is an exponent. Using properties like log(a^b) = b*log(a) allows us to bring down exponents and solve for the variable algebraically.
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Change of Base Property
Rounding and Exact vs. Approximate Solutions
Some solutions to equations are irrational and cannot be expressed exactly as fractions or decimals. Understanding when to provide exact forms (like logarithmic expressions) versus decimal approximations rounded to a specific place value is important for clear and accurate answers.
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