1(a, b) = (1a, 1b) = (a, b). Show that M2,2, the set of all 2 × 2 matrices, is a vector space. Solution. We need to check each and every axiom of a vector space to know that it is in fact a vector space. A1: Let a1,1 a1,2 a2,1 a2,2 , b1,1 b2,1. b2,2 b1,2 ∈ M2,2. Then.