(a) Find an example of a 3 x 3 matrix M and a 3 x 3 matrix N with entries in R such that M.0 == N. 0 but that M 1 N 1 (b) If A, B are 3 x 3 matrices with entries in R and Av = Bu for every vector v in R, show that A ===== B. (Hint: Be careful here. Since v is a vector, it makes no sense to simply divide both sides by v.)