SOLUTION: Show that 3+log2(9)=log2(8)

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Question 1205396: Show that 3+log2(9)=log2(8)
Found 3 solutions by ikleyn, math_tutor2020, greenestamps:
Answer by ikleyn(52905) About Me  (Show Source):
You can put this solution on YOUR website!
.
Show that 3+log2(9)=log2(8)
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This can not happen because this can never happen.


The Math composer,  who created this post  (so called Math problem),
deserves very serious reprobation.


From the distance of thousand miles,  it is clearly seen
that this person does understand  NOTHING  in  Math.



Answer by math_tutor2020(3817) About Me  (Show Source):
You can put this solution on YOUR website!

3+%2B+log%282%2C%289%29%29+=+log%282%2C%288%29%29

3++=+log%282%2C%288%29%29+-+log%282%2C%289%29%29

3++=+log%282%2C%288%2F9%29%29 Used log rule log(A)-log(B) = log(A/B)

2%5E3++=+8%2F9%29 Converting from log form to exponential form

8++=+8%2F9%29 We get a contradiction, so the original equation is false.

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Another way to show the contradiction:
3+%2B+log%282%2C%289%29%29+=+log%282%2C%288%29%29

3+%2B+log%282%2C%289%29%29+=+log%282%2C%282%5E3%29%29

3+%2B+log%282%2C%289%29%29+=+3%2Alog%282%2C%282%29%29 Using log rule log(A^B) = B*log(A) to pull down the exponent.

3+%2B+log%282%2C%289%29%29+=+3%2A1 Log base b of itself is 1.

3+%2B+log%282%2C%289%29%29+=+3

log%282%2C%289%29%29+=+0 The 3's cancel when subtracting them from both sides.

9+=+2%5E0 Converting from log form to exponential form.

9+=+1 which is a contradiction

Answer by greenestamps(13215) About Me  (Show Source):
You can put this solution on YOUR website!


Without doing any work on the problem, it should be clear (if you know anything about logarithms) that log2(9) by itself is greater then log2(8), so 3 + log2(9) can't be equal to log2(8).

The problem is flawed; or you posted it incorrectly....