2 câu trả lời
$Ư(10)=\{\pm1;\pm2;\pm5;\pm10\}$
$Ư(45)=\{\pm1;\pm3;\pm5;\pm9;\pm15;\pm45\}$
$\Rightarrow ƯC(10;45)=\{\pm1;\pm5\}$.
Ta có : $10 = 2.5\,\,\,;\,\,\,\,45 = {3^2}.5$
$ \Rightarrow ƯCLN(10 ; 45) = 5$
$ \Rightarrow ƯC(10; 45) =U(5)= \left\{ {-1;-5;1;5} \right\}$
