Solve Product of Logarithms: log₄(9) × log₁₃(7) Evaluation

Question

log49×log137= \log_49\times\log_{13}7=

Video Solution

Solution Steps

00:00 Solve
00:03 We'll use the formula for multiplication of logarithms
00:07 We'll exchange between the bases of the logarithms
00:13 We'll use this formula in our exercise
00:33 And this is the solution to the question

Step-by-Step Solution

To solve the problem log49×log137 \log_49 \times \log_{13}7 , we'll employ the change of base formula for logarithms:

  • Step 1: Apply the change of base formula to each logarithm.
  • Step 2: Use logarithm properties and analyze transformations for a match with choices.

Now, let's work through each step:
Step 1: Use the change of base formula on each log:
log49=loga9loga4 \log_49 = \frac{\log_a 9}{\log_a 4} and log137=logb7logb13 \log_{13}7 = \frac{\log_b 7}{\log_b 13} , where a a and b b are arbitrary positive bases.
Both expressions use a common base not relevant for the solution but illustrate the transformation ability.

Step 2: We'll recombine and look for products that can utilize these, such as:

log139×log47 \log_{13}9\times\log_47 becomes loga9loga13×logb7logb4 \frac{\log_a 9}{\log_a 13} \times \frac{\log_b 7}{\log_b 4}
Applying cross multiplication or iteration forms, the structure aligns with the multiplication identity for this problem due to independence of base.

Therefore, the transformed expression satisfying the criteria is log139×log47 \log_{13}9\times\log_47 .

Answer

log139×log47 \log_{13}9\times\log_47


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