In: Advanced Math
8.Let a and b be integers and d a positive
integer.
(a) Prove that if d divides a and d divides b, then d divides both
a + b and a − b.
(b) Is the converse of the above true? If so, prove it. If not,
give a specific example of a, b, d showing
that the converse is false.
9. Let a, b, c, m, n be integers. Prove that if a divides each of b
and c, then a divides nb + mc.
This is the required solution for the given question no 8 (part a,b,c) .Hope it will help you . Please give a Thumbs up .Thank you.