Please help me find the solution to these practices problems. Please show work and number the questions.

3: Determine whether the subset of the given set forms a subspace. If it is not a subspace, explain why. The subset W =1 X2 E R3 x1 6 R , x2 E R } of R3. This is the set of all vectors in IRS whose third component is 1. 4: Determine whether the vector v is in the span of S. If so, write v as a linear combination of the vectors in S. = a 5: Determine whether the set S spans IR3. S = V1 = -2 6: Determine whether the set S is linearly independent or linearly dependent