Giải thích các bước giải:
Ta có:
$2^{2022}=(2^{3})^{674}$
$\to 2^{2022}=8^{674}$
Ta có $8\equiv -1(mod 9)$
$\to 8^{674}\equiv (-1)^{674}(mod 9)$
$\to 8^{674}\equiv 1(mod 9)$
$\to 2^{2022}\equiv 1(mod 9)$
Mà $2^5=32\equiv 5(mod 9)$
$\to 2^{2022}+2^5\equiv 1+5(mod 9)$
$\to 2^{2022}+2^5\equiv 6(mod 9)$
$\to 2^{2022}+2^5\quad\not\vdots\quad 9$