23 mar 2015, 20:35
Me ajudem por favor!
(5)/(10^-2) = (5^x) . (10^3)
23 mar 2015, 22:08
Boa noite,
\(\frac{5}{10^{-2}}=5^{x}\cdot 10^{3}\Leftrightarrow 5\cdot 10^{2}=5^{x}\cdot 10^{3}\Leftrightarrow 5^{x}=\frac{5\cdot 10^{2}}{10^{3}}\Leftrightarrow 5^{x}=\frac{5}{10}\Leftrightarrow 5^{x}=\frac{1}{2}\Leftrightarrow \log _{5}5^{x}=\log _{5}\left ( \frac{1}{2} \right )\Leftrightarrow x=\log _{5}\left ( \frac{1}{2} \right )\Leftrightarrow x=-\log _{5}2\)