Let a,b be nonzero integers with (a,b)=1. Compute (a+b, a-b).?

Answer 1

well if a+b not zero and
a-b not zero then
(a+b, a-b) = 1

[ i assume you mean that if a,b nonzero then (a,b)=1 ]

for all other values you dont define (a,b) so it is not defined.

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