SOLUTION: 81=3^X How do you find X?

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Question 415204: 81=3^X How do you find X?
Found 2 solutions by nerdybill, Alan3354:
Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
81=3%5Ex
take log base 3 of both sides:
log%283%2C81%29=log%283%2C3%5Ex%29
log%283%2C3%5E4%29=log%283%2C3%5Ex%29
+4+=+x+

Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
If you know that 81 = 3^4, then
3%5E4+=+3%5Ex
x = 4
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If you don't know that:
log(81) = x*log(3)
x = log(81)/log(3)
x = 4