Proof problem #.3 Let A be an n x k matrix, and let B be a k x m matrix. AB is their product n x m matrix. Prove: . If AB is one-to-one as a linear transformation, then so is B. . If AB is onto as a linear transformation, then so is A. Due: week 8 common pitfalls . As before, you don't know the values of n, k, or m, nor any of the terms of the matrices. You cannot make an argument based on the sizes of A or B, or using the number of leading terms of the matrices