Solve Complex Logarithm Expression: (1/2)log₂4 × log₃8 + log₃9 × log₃7

Question

12log24×log38+log39×log37= \frac{1}{2}\log_24\times\log_38+\log_39\times\log_37=

Video Solution

Solution Steps

00:00 Solve
00:05 Calculate the logarithm according to its definition
00:13 Isolate and find X
00:17 Use the same method and calculate this logarithm
00:26 These are the solutions for the logarithms
00:32 Substitute and continue solving
00:43 Simplify what we can
00:48 Use the power rule for logarithms and move the 2 to the exponent
01:02 Use the formula for adding logarithms
01:13 Solve the exponent
01:21 And this is the solution to the question

Step-by-Step Solution

We break it down into parts

log24=x \log_24=x

2x=4 2^x=4

x=2 x=2

log39=x \log_39=x

3x=9 3^x=9

x=2 x=2

We substitute into the equation

122log38+2log37= \frac{1}{2}\cdot2\log_38+2\log_37=

1log38+2log37= 1\cdot\log_38+2\log_37=

log38+log372= \log_38+\log_37^2=

log38+log349= \log_38+\log_349=

log3(849)=log3392 \log_3\left(8\cdot49\right)=\log_3392 x=2 x=2

Answer

log3392 \log_3392


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