Chapter 4: Problem 325
Use the definition of a logarithm to solve the equation. \(10-4 \ln (9-8 x)=6\)
Short Answer
Expert verified
The solution to \(10 - 4 \ln(9 - 8x) = 6\) is approximately \(x \approx 0.78525\).
Step by step solution
01
Simplify the Equation
Start by isolating the logarithmic term. Move everything else to the other side of the equation:\[ 10 - 4 \ln (9 - 8x) = 6 \]Subtract 10 from both sides:\[ -4 \ln (9 - 8x) = 6 - 10 \]This simplifies to:\[ -4 \ln (9 - 8x) = -4 \]
02
Divide by the Coefficient of Logarithm
The next step is to get rid of the coefficient of the logarithm. Divide the entire equation by -4:\[ \ln (9 - 8x) = \frac{-4}{-4} \]Which simplifies to:\[ \ln (9 - 8x) = 1 \]
03
Exponentiate to Remove Logarithm
Exponentiate both sides to eliminate the natural logarithm. Recall that if \ln(y) = x, then \exp(x) = y:\[ 9 - 8x = e^1 \]\[ 9 - 8x = e \]
04
Solve for x
To solve for x, rearrange the equation:\[ 9 - e = 8x \]Divide both sides by 8:\[ x = \frac{9 - e}{8} \]
05
Final Result
Substitute the value of e (approximately 2.718) to get a numerical value for x:\[ x \approx \frac{9 - 2.718}{8} \]\[ x \approx \frac{6.282}{8} \]\[ x \approx 0.78525 \]
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Exponentiation
Exponentiation is a fundamental mathematical operation that involves raising a number, known as the base, to the power of an exponent. This operation is denoted by the use of a superscript. For example, in the expression \( a^b \), \( a \) is the base and \( b \) is the exponent. The result is equal to multiplying the base by itself \( b \) times.Key points about exponentiation:
- It's an important operation in algebra and is used in solving equations.
- Exponentiation can be easily reversed using logarithms.
- The inverse operation of exponentiation is known as finding the logarithm.
Natural Logarithms
Natural logarithms are a special type of logarithm that use the mathematical constant \( e \) (approximately 2.718) as their base. The notation for a natural logarithm is \( \ln(x) \). Natural logarithms are particularly useful in calculus and complex exponential growth models.Key aspects of natural logarithms include:
- The natural logarithm of \( e \) is 1, since \( \ln(e) = 1 \).
- They possess unique properties that simplify many algebraic expressions.
- Natural logarithms are the inverse function of exponentiation when the base is \( e \).
Solving Equations
Solving equations involves finding the value of the unknown variable that makes the equation true. It is a fundamental skill in mathematics and involves various methods depending on the type of equation.For logarithmic equations, such as the one discussed in the exercise, the steps to solve are:
- First, simplify the equation by moving terms around to isolate the logarithmic expression.
- Next, if a coefficient is present with the logarithm, divide the entire equation by this coefficient to isolate the logarithmic term completely.
- Then, apply exponentiation to remove the natural logarithm. This step involves using the property \( \ln(y) = x \) implies \( y = e^x \).
- Finally, solve for the unknown variable by rearranging the equation into a standard form and performing any arithmetic operations necessary.