1. The problem statement, all variables and given/known data Hey, I'm trying to figure out whether A = [x+1,0] is a subspace... I know it's probably simple but what i'm confused is that.... 2. Relevant equations 3. The attempt at a solution u+v must be an element of A. let u = [x1+1,0] and v=[x2+1,0]. Adding them together gives you [x1+x2+2,0], where (x1+x2) = x. Therefore it wouldn't be a subspace because you now have the form [x+2,0] which is not the same? But if I look at it, [x1+x2+2,0] should be a subspace because you can get the same value with [x+1, 0] (let x1, x2 = -1 and let x = -1, both get 0 vector, for example) Thanks for any help!