Im trying to do test corrections and there are no problems like this in my math book :/ help please!
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Take the base 2 log of both sides and bring down the exponents to get (x+7)log8=(2x-1)log16 where the log is base 2 so that log8=3 and log16=4. Thus 3x+21=8x-4 or 25=5x so x=5.