... the set of all linear combinations of the elements of S is a subgroup of Z, and its positive generator is the gcd of the elements of S Exercise Show that the gcd of S = {90, 70, 42} is 2, and find ... teach abstract and linear algebra as one coherent discipline rather than as two separate ones Teaching abstract algebra and linear algebra as distinct courses results in a loss of synergy and a ... of a and b Note that c is a multiple of a and b, and if n is a multiple of a and b, then n is a multiple of c Finally, if a and b are positive, their least common multiple is c = ab/(a, b), and...