Prove that for every integer n there exist integers j and k

Prove that for every integer n there exist integers j and k for which n=3j+5k

I need to keep this as an abstract. I cannot use real numbers.

Solution

let n =8

we can write, 8=3*1+5*1

compairing with  n=3j+5k

j=1 , k =1

let n=9

9=3*3+5*0

j=3, k=0

hence for every integer n there exist integers j and k for which n=3j+5k