8.Let a and b be integers and d a positiveinteger.
(a) Prove that if d divides a and d divides b, then d divides botha + 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 band c, then a divides nb + mc.
