A. The equation Ax = b is referred to as a vector equation. b. A vector b is a linear combination of the columns of a matrix A if and only if the equation Ax = b has at least one solution.

c. The equation Ax = b is consistent if the augmented matrix [A b] has a pivot position in every row.

d. The first entry in the product Ax is a sum of products.

e. If the columns of an m × n matrix A span ℝm, then the equation Ax = b is consistent for each b in ℝm.

f. If A is an m × n matrix and if the equation Ax = b is inconsistent for some b in ℝm, then A cannot have a pivot position in every