For the first one, we can make use of the fact that f and g are inverses, so we can cancel to get f(f(27))=f(3)=1.
For the second one, set
\(7^x\cdot7^7=8^x\)
\(7^7=\frac{8^x}{7^x}=\frac{8}{7}^x\)
\(log_\frac{8}{7}{7^7}=x\)
So b is \(\frac{8}{7}\).
For the third one, the expression is equal to
-1/6 + 0 + 1/6 + 1/3 + 1/2 + \(log_{64}{n}\)=2
\(log_{64}{n}=\frac{7}{6}\)
\(n=128\)
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