Solve the Log Equation: log₂7·log₄8·log₃x² = log₂4·log₄7·log₃8

Question

log27log48log3x2=log24log47log38 \log_27\cdot\log_48\cdot\log_3x^2=\log_24\cdot\log_47\cdot\log_38

?=x

Video Solution

Solution Steps

00:00 Solve
00:04 Let's use the logical multiplication formula, we'll switch between the numbers
00:16 Let's use this formula in our exercise
00:34 Let's reduce what we can
00:52 Let's use the formula again in our exercise
01:04 Let's reduce what we can
01:18 Let's solve
01:28 When taking a root, there are always 2 possibilities, positive and negative
01:33 Let's check the domain for finding the solution
01:38 And this is the solution to the question

Step-by-Step Solution

To solve the given logarithmic equation, we'll use properties of logarithms and simplification:

  • First, let's restate the equation:
    log27log48log3x2=log24log47log38 \log_2 7 \cdot \log_4 8 \cdot \log_3 x^2 = \log_2 4 \cdot \log_4 7 \cdot \log_3 8 .
  • Using the logarithmic property logbxn=nlogbx\log_b x^n = n \log_b x, we can express log3x2 \log_3 x^2 as 2log3x 2\log_3 x .
  • We apply the change of base formula:
    logab=logcblogca\log_a b = \frac{\log_c b}{\log_c a}. We compute each component by using base 10 for simplification:
  • log48\log_4 8 can be simplified using change of base to log28log24=3log222log22=32\frac{\log_2 8}{\log_2 4} = \frac{3\log_2 2}{2\log_2 2} = \frac{3}{2}.
  • So, simplify the equation step by step:
  • log27322log3x=log24log47log38\log_2 7 \cdot \frac{3}{2} \cdot 2 \log_3 x = \log_2 4 \cdot \log_4 7 \cdot \log_3 8.
  • Continue by simplifying the right-hand side similarly and equating terms, yielding simplified expressions.
  • Solve the reduced or deduced expression algebraically, yielding potential solutions for x x .
  • Perform checks to consider values of x x that are consistent and validate them against the constraints.

Through simplification and substitution, we confirm that the solution to the original equation is x=2,2 x = -2, 2 .

Answer

2,2 -2,2


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