Which of the following statements are true?
A. If A is an m × n matrix whose columns do not span Rᵐ , then the equation Ax = b is inconsistent for some b in Rᵐ
B. If the equation Ax-b is inconsistent, then b is not in the set spanned by the columns of A.
C. 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.
D. The equation Ax -b is referred to as a vector equation.
E. The equation Ax-b is consistent if the augmented matrix [ A b ] has a pivot position in every row
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 row.