c; (3n+2)\(⋮\)(2n-1)
(2n-1)+(n+3)\(⋮\)(2n-1)
Vì (2n-1)\(⋮\)(2n-1)=>(n+3)\(⋮\)(2n-1)
Vì (n+3)\(⋮\)(2n-1)=>2(n+3)\(⋮\)(2n-1)
(2n+6)\(⋮\)(2n-1)
(2n+6)=(2n-1)+7\(⋮\)(2n-1)
Vì (2n-1)\(⋮\)(2n-1)=>7\(⋮\)(2n-1)
Vậy 2n-1ϵƯ(7)={1;7}
Với 2n-1=1=>2n=2=>n=1
2n-1=7=>2n=8=>n=4
Vậy n \(\in\){1;4}