1. Suppose the coefficient matrix of a linear system of four equations in four variables has a pivot in each column. Explain why the system has a unique solution.
2. What must be true of a linear system for it to have a unique solution?
Select all that apply.
A. The system has no free variables.
B. The system has one more equation than free variable.
C. The system is inconsistent.
D. The system is consistent. Your answer is correct.
E. The system has at least one free variable.
F. The system has exactly one free variable.