Question 197090
If f(x)=3^x and 
g(x)=log base 9 of x, find:
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You need f^(-1)(x)
Starting with f(x) = 3^x
Interchange x and y to get:
x = 3^y
Solve for y:
y = log(base3)x
So f^(-1)(x) = log(base3)x
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Now try your problem:

f^-1(g(9)) = f^(-1)[log(base9)9]
= f^(-1)[1]
= log(base3)1
= 0
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That's pretty complicated.  Hope that helps.
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Cheers,
Stan H.