Question

решите уравнение 5^x*4^-x=0,8

Answer 1

5^x*4^-x=0,8

5^x/4^x = 4/5

(5/4)^x = (5/4)^(-1)

x = -1

Answer 2

$5^{x}* 4^{-x}=0,8\\5^{x}* (frac{1}{4}) ^{x}= frac{8}{10}\\(frac{5}{4}) ^{x}= frac{4}{5}\\(frac{5}{4}) ^{x}=( frac{5}{4}) ^{-1}\\x=-1$