1. The problem statement, all variables and given/known data Let S be the form of (a, b,c ,d )in R4, given a not equal to 0. Find the basis that is subset of S. 2. Relevant equations 3. The attempt at a solution I got a(1,0,0,0), b(0,1,0,0), c(0,0,1,0), d(0,0,0,1) as basis. a not = 0 But i wasn't sure what the significances of a not = to 0 means Any help would be appreciated. Thanks in advance.