Math Problem Statement

Solve the logarithmic expressions: (1) log_2 16 + log_2 100, (2) log_5 98 - log_5 4, (3) 2log_3 9 + log_3 81.

Solution

Let me transcribe and solve the logarithmic expressions from the image.

Transcribed Problems:

  1. log216+log2100\log_2 16 + \log_2 100
  2. log598log54\log_5 98 - \log_5 4
  3. 2log39+log3812\log_3 9 + \log_3 81

Solution:

1. log216+log2100\log_2 16 + \log_2 100

Using the logarithmic property logb(m)+logb(n)=logb(mn)\log_b(m) + \log_b(n) = \log_b(m \cdot n): log216+log2100=log2(16100)=log21600\log_2 16 + \log_2 100 = \log_2 (16 \cdot 100) = \log_2 1600 Next, express 16001600 as a power of 22: 1600=2625=26521600 = 2^6 \cdot 25 = 2^6 \cdot 5^2 Thus: log21600=6+log2(25)=6+log(25)log(2)(if exact value required).\log_2 1600 = 6 + \log_2(25) = 6 + \frac{\log(25)}{\log(2)} \quad \text{(if exact value required)}.


2. log598log54\log_5 98 - \log_5 4

Using the logarithmic property logb(m)logb(n)=logb(mn)\log_b(m) - \log_b(n) = \log_b\left(\frac{m}{n}\right): log598log54=log5(984)\log_5 98 - \log_5 4 = \log_5\left(\frac{98}{4}\right) Simplify: 984=24.5solog5(984)=log5(24.5)\frac{98}{4} = 24.5 \quad \text{so} \quad \log_5\left(\frac{98}{4}\right) = \log_5(24.5)


3. 2log39+log3812\log_3 9 + \log_3 81

Use the property alogb(m)=logb(ma)a\log_b(m) = \log_b(m^a): 2log39=log3(92)=log3(81)2\log_3 9 = \log_3(9^2) = \log_3(81) So: 2log39+log381=log3(81)+log3(81)2\log_3 9 + \log_3 81 = \log_3(81) + \log_3(81) Using the addition property: log3(81)+log3(81)=log3(8181)=log3(6561)\log_3(81) + \log_3(81) = \log_3(81 \cdot 81) = \log_3(6561) Since 6561=386561 = 3^8: log3(6561)=8\log_3(6561) = 8


Final Answers:

  1. log21600=6+log2(25)\log_2 1600 = 6 + \log_2(25) or 6+log(25)log(2)6 + \frac{\log(25)}{\log(2)}.
  2. log5(24.5)\log_5(24.5).
  3. 88.

Would you like detailed steps for any part of these solutions or approximations for logarithms?


Related Questions:

  1. How are logarithmic properties applied to simplify expressions?
  2. What are common techniques to estimate logarithmic values?
  3. Can you generalize the use of logb(mn)=nlogb(m)\log_b(m^n) = n\log_b(m)?
  4. How does change of base simplify solving logs like log5(24.5)\log_5(24.5)?
  5. Why is logb(1)=0\log_b(1) = 0 always true?

Tip:

Always simplify logarithmic arguments to their prime factors for quicker calculations.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Logarithms
Properties of Logarithms
Exponentiation

Formulas

log_b(m) + log_b(n) = log_b(m * n)
log_b(m) - log_b(n) = log_b(m / n)
a * log_b(m) = log_b(m^a)

Theorems

Properties of Logarithms

Suitable Grade Level

Grades 9-12