Giải thích các bước giải:
a.Ta có:
$8^5+2^{11}=(2^3)^5+2^{11}=2^{15}+2^{11}=2^{11}(2^4+1)=2^{11}\cdot 17\quad\vdots\quad 17$
b.Ta có:
$19^{19}+69^{19}\quad\vdots\quad 19+69=88\quad\vdots\quad 44$
c.Ta có:
$2021^{2019}+2019^{2021}\quad\vdots\quad 2021+2019=4040\quad\vdots\quad 2020$