Part a) Consider the space of all vectors with 3 coordinates, which we label x, y and z. The inter- section between the planes x+y+3z = 6 and xy+z = 4 is a . On this , there is/are exactly (how many) points with z = 2. This/these points is/are . Similarly there is/are exactly points with z = 0 and it is/they are . Justify all your answers Part b) By trial and error, find two 2 2 matrices A and B, neither of them having all 0 entries, but such that AB = 0. Here 0 is the zero matrix, i.e., a matrix with all entries 0