Question

Answer 1

\(ƯCLN\left(a,b\right)=5\Rightarrow\left\{{}\begin{matrix}a=5k\\b=5q\end{matrix}\right.\left(k,q\in N\text{*}\right)\\ \Rightarrow ab=25kq=150\\ \Rightarrow kq=6\\ \Rightarrow\left(k;q\right)\in\left\{\left(1;6\right);\left(6;1\right);\left(2;3\right);\left(3;2\right)\right\}\\ \Rightarrow\left(a,b\right)\in\left\{\left(5;30\right);\left(30;5\right);\left(10;15\right);\left(15;10\right)\right\}\)

Answer 2

\(\left(a,b\right)\in\left\{\left(5;30\right);\left(30;5\right);\left(10;15\right);\left(15;10\right)\right\}\)