Solve each logarithmic equation in Exercises 49–92. Be sure to reject any value of x that is not in the domain of the original logarithmic expressions. Give the exact answer. Then, where necessary, use a calculator to obtain a decimal approximation, correct to two decimal places, for the solution. 2 log x=log 25
Ch. 4 - Exponential and Logarithmic Functions

Chapter 5, Problem 82
Expand:
Verified step by step guidance1
Rewrite the expression inside the logarithm to make it easier to work with. The expression is \( \frac{4\sqrt{x}}{64y^3} \). Recognize that \(4\sqrt{x} = 4x^{1/2}\) and \(64 = 8^2\).
Use the logarithm property for division: \( \log_b \left( \frac{M}{N} \right) = \log_b(M) - \log_b(N) \). So, \( \log_8 \left( \frac{4x^{1/2}}{64y^3} \right) = \log_8(4x^{1/2}) - \log_8(64y^3) \).
Apply the logarithm property for multiplication: \( \log_b(MN) = \log_b(M) + \log_b(N) \). Expand both terms: \( \log_8(4) + \log_8(x^{1/2}) - [\log_8(64) + \log_8(y^3)] \).
Use the power rule of logarithms: \( \log_b(a^c) = c \log_b(a) \). Rewrite \( \log_8(x^{1/2}) = \frac{1}{2} \log_8(x) \) and \( \log_8(y^3) = 3 \log_8(y) \).
Now, the expression is \( \log_8(4) + \frac{1}{2} \log_8(x) - \log_8(64) - 3 \log_8(y) \). This is the fully expanded form using logarithm properties.

Verified video answer for a similar problem:
This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
5mWas this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Properties of Logarithms
Logarithmic properties such as the product, quotient, and power rules allow us to simplify complex logarithmic expressions. For example, log_b(M/N) = log_b(M) - log_b(N) and log_b(M^k) = k * log_b(M). These rules help break down the given expression into manageable parts.
Recommended video:
Change of Base Property
Change of Base and Simplifying Bases
Understanding how to express numbers as powers of the logarithm's base is crucial. Here, recognizing that 8, 4, and 64 are powers of 2 allows simplification. This helps rewrite the expression inside the log in terms of base 8 or base 2 for easier expansion.
Recommended video:
Change of Base Property
Radicals and Exponents
Converting radicals to fractional exponents is essential for simplifying expressions inside logarithms. For example, the fourth root of x is x^(1/4). This conversion allows the use of the power rule of logarithms to bring exponents outside the log for easier manipulation.
Recommended video:
Guided course
Rational Exponents
Related Practice
Textbook Question
1005
views
Textbook Question
Solve each logarithmic equation in Exercises 49–92. Be sure to reject any value of x that is not in the domain of the original logarithmic expressions. Give the exact answer. Then, where necessary, use a calculator to obtain a decimal approximation, correct to two decimal places, for the solution. log(x+4)−log 2=log(5x+1)
1283
views
Textbook Question
In Exercises 83–88, let logb 2 = A and logb 3 = C and Write each expression in terms of A and C.
logb (3/2)
819
views
Textbook Question
Use a graphing utility and the change-of-base property to graph each function. y = log2 (x + 2)
680
views
Textbook Question
Evaluate or simplify each expression without using a calculator. log 100
977
views
Textbook Question
Evaluate or simplify each expression without using a calculator. log 107
885
views
