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

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