Respuesta :

Answer:

Step-by-step explanation:

Assume there exists integer k such that 3k=a+1.

4+7a

=7a+4

=7(a+1)-3

=7(3k)-3

=3(7k-1)

This implies that if there exists integer k such that 3k=a+1 then there is integer 7k-1 such that 3(7k-1)=4+7a