Zał: x > 0
[tex] log_{ \frac{1}{3} }(x) = - 4 \\ x = ({ \frac{1}{3}) }^{- 4} \\ x = {3}^{4} \\ x = 81[/tex]x > 0
ODP: x = 81
[tex]log_{a} b=c~~\Leftrightarrow ~~a^{c} =b~~zal.~~b>0,~~a>0,~~a\neq 1\\\\log_{\frac{1}{3} } x=-4~~zal.~~x>0\\\\x=(\dfrac{1}{3} )^{-4} \\\\x=(\dfrac{3}{1} )^{4} \\\\x=3^{4} \\\\x=81~~\land ~~x>0~~\Rightarrow ~~x=81\\\\Odp:~~ x=81[/tex]
