1. The problem statement, all variables and given/known data determine if the space is a subspace testing both closure axioms. in R^2 the set of vectors (a,b) where ab=0 2. Relevant equations 3. The attempt at a solution i just used the sum and product which are the closure axioms. But at the end how do you tell if the resulting vector is a subspace? (a,b) + (c,d) = (a+c, b+d) (a+c)(b+d)=0 then ab+cb + ad+dc=0 ab+cb = -ad-dc then ??? x=constant x(a,b) = (xa,xb) then abx^2 =0 then?????