Answer
(a) $\frac{1}{4}$
(b) $-\frac{1}{2}$
(c) $\frac{3}{2}$
Work Step by Step
Quick overview of the main idea of logarithms:
$\log_x{a}=b$; Where $x^b=a$
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(a) $\log_4{\sqrt2}=\log_4{4^{\frac{1}{4}}}=\frac{1}{4}$
(b) $\log_4{\frac{1}{2}}=\log_4{4^{-\frac{1}{2}}}=-\frac{1}{2}$
(c) $log_4{8} = \log_4{4^{\frac{3}{2}}}=\frac{3}{2}$