Math Problem Statement

Write the expression using a single logarithm: log_b(2x) - 3log_b(4x) - 5log_b(x)

Solution

The given expression is:

logb(2x)3logb(4x)5logb(x)\log_b(2x) - 3\log_b(4x) - 5\log_b(x)

We need to combine this expression into a single logarithm using logarithmic properties.

Step-by-step approach:

  1. Apply the power rule: The logarithmic power rule states that alogb(x)=logb(xa)a\log_b(x) = \log_b(x^a). Let's apply this to the terms with coefficients:

    • logb(2x)\log_b(2x) remains as it is.
    • 3logb(4x)=logb((4x)3)=logb(64x3)3\log_b(4x) = \log_b((4x)^3) = \log_b(64x^3)
    • 5logb(x)=logb(x5)5\log_b(x) = \log_b(x^5)

    Now the expression becomes: logb(2x)logb(64x3)logb(x5)\log_b(2x) - \log_b(64x^3) - \log_b(x^5)

  2. Apply the subtraction rule: The subtraction rule of logarithms states that logb(A)logb(B)=logb(AB)\log_b(A) - \log_b(B) = \log_b\left(\frac{A}{B}\right). We can now combine the terms step by step.

    First, combine the first two terms: logb(2x64x3)=logb(264xx3)=logb(1321x2)=logb(132x2)\log_b\left(\frac{2x}{64x^3}\right) = \log_b\left(\frac{2}{64} \cdot \frac{x}{x^3}\right) = \log_b\left(\frac{1}{32} \cdot \frac{1}{x^2}\right) = \log_b\left(\frac{1}{32x^2}\right)

    Now, include the third term: logb(132x2)logb(x5)=logb(132x2x5)=logb(132x7)\log_b\left(\frac{1}{32x^2}\right) - \log_b(x^5) = \log_b\left(\frac{\frac{1}{32x^2}}{x^5}\right) = \log_b\left(\frac{1}{32x^7}\right)

Thus, the final expression as a single logarithm is:

logb(132x7)\log_b\left(\frac{1}{32x^7}\right)

Final Answer:

logb(132x7)\log_b\left(\frac{1}{32x^7}\right)

Would you like further details on logarithmic properties or have any other questions?


Here are 5 related questions to explore:

  1. What are the properties of logarithms?
  2. How does the power rule for logarithms work in other contexts?
  3. Can logarithms be applied to non-algebraic problems, such as real-world scenarios?
  4. How can we simplify logarithmic expressions involving division?
  5. What is the significance of the base in logarithms?

Tip: When simplifying logarithms, always look for opportunities to apply the power and quotient rules to reduce the number of terms.

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Math Problem Analysis

Mathematical Concepts

Logarithms
Algebra
Logarithmic Properties

Formulas

a * log_b(x) = log_b(x^a) (Power rule)
log_b(A) - log_b(B) = log_b(A/B) (Subtraction rule)

Theorems

Logarithmic Power Rule
Logarithmic Quotient Rule

Suitable Grade Level

Grades 10-12