Consider the following set of vectors in R?: 2 1 2 1 0 -7 3 2 1 Does the set span R?? Justify your answer. Consider the following vectors in R: 1 1 1 0 1 1 u = |0 ,ua= 1|0 ...., u, = |1 0 0 1 (The vector u; has its first entries equal to 1, and the remaining entries equal to 0.) Determine whether uy, .. ., u,, span R without using any computation