## Precalculus: Mathematics for Calculus, 7th Edition

$Evaluate$ $the$ $expression$ $without$ $using$ $a$ $calculator:$ $\log 25 + \log 4$ Use the First Law of Logarithms: $\log (AB) = \log A + \log B$ $$\log 25 + \log 4 = \log(25\times4)$$ $$\log 100 = \log_{10} 100$$ Rewrite 100 as $10^2$ $$\log_{10} 10^2$$ Use the Third Property of Logarithms: $\log_a a^x =x$ $$\log_{10} 10^2 = 2$$