Compute the product using (a) the definition where Ax is the linear combination of the columns of A using the corresponding entries in x as weights, and (b) the row-vector

rule for computing Ax. If a product is undefined, explain why. (a) Compute the product using the definition where Ax is the linear combination of the columns of A using the corresponding entries in x as weights. If the product sun defined, explain why. Select the correct choice below and, if necessary, fill in any answer boxes to complete your choice. Ах- B. The matrix-vector Ax is not defined because the number of rows in matrix A does not match the number of entries in the vector x. The matrix-vector Ax is not defined because the number of columns in matrix A does not match the number of entries in the vector x.