check!
posted by Anonymous .
here is the question:
log5(x4)= log7x solve for x.
These are just base 10 logs.
log100 = 2
This equation has the same format as log 40 = log (2x20)
Since both sides have log base 10, you divide by log base 10 and end up with 5(x4) = 7x, so 5x 20 =7x x=10
One doesn't exactly "divide by base 10".
log5(x4)= log7x solve for x.
take each side as exponents to the base 10, or
10^(log5(x4))= 10^(log7x)
then
5(x4) = 7x
and x= 10
check...
log (5(14)= log 70
log (70)=log(70) and it checks
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