Question

Задание по алгебре 8 класс

Answer 1

$2^{3-k}+2^{1-k}+5cdot 2^{-k}=40\\2^3cdot 2^{-k}+2cdot 2^{-k}+5cdot 2^{-k}=40\\2^{-k}cdot (2^3+2+5)=40\\2^{-k}cdot 15=40\\2^{-k}= frac{40}{15}\\2^{-k}=2 frac{2}{3}$

Answer 2

$2^{3-k}+ 2^{1-k}+5* 2^{-k}=40\\ 2^{3}* 2^{-k} + 2^{1}* 2^{-k} +5* 2^{-k}=40\\8* 2^{-k}+2* 2^{-k} +5* 2^{-k}=40\\15* 2^{-k}=40\\ 2^{-k} =2 frac{2}{3}$