Question 5 A system of equations can be written as Ax - b, where A is a 4 x 4 matrix and x and b are Not yet answered vectors. Which of the following statements is incorrect? Marked out of 0.50 Select one: Flag O If A- exists, it is a 4 x 4 matrix. question . If A = 0, there must be no solution. O If A # 0 , there must be a unique solution. O If two rows of A are the same, A = 0. O If A = 0, A- does not exist