Question

помогите 1 вариант решить

Answer 1

$27^x=81 \ 3^{3x}=3^4 \ 3x=4 \ x= frac{4}{3} \ OTBET: frac{4}{3}$
$sqrt[4]{8^x} =16 \ 8^{ frac{x}{4} }=8^2 \ frac{x}{4} =2 \ x=8 \ OTBET:8$
$3^{x+1}+2*3^{x-1}=5 \ 3*3^x+2* frac{1}{3}*3^x =5 \ t=3^x \ 3t+ frac{2}{3}t=5 \ 9t+2t=15 \ 11t=15 \ t= frac{15}{11} \ 3^x= frac{15}{11} \ x=log_3 ( frac{15}{11}) \ OTBET: log_3 ( frac{15}{11} )$
$25^x-8*5^x-9=0$
$5^x=t \ t^2-8t-9=0 \ left { {{t=9} atop {t=-1}} right. \ left { {{5^x=9} atop {5^x neq -1}} right. \ x=log_59 \ OTBET: log_59$