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solution of the homogeneous system
(verify).
Bases for Row Spaces, Column Spaces, and Nullspaces
We first developed elementary row operations for the purpose of solving linear systems, and we know from that work that
performing an elementary row operation on an augmented matrix does not change the solution set of the corresponding linear
system. It follows that applying an elementary row operation to a matrix A does not change the solution set of the corresponding
linear system , or, stated another way, it does not change the nullspace of A. Thus we have the following theorem.
THEOREM 5.5.3
Elementary row operations do not change the nullspace of a matrix.
EXAMPLE 4 Basis for Nullspace
Find a basis for the nullspace of
Solution
The nullspace of A is the solution space of the homogeneous system
In Example 10 of Section 5.4 we showed that the vectors
form a basis for this space.
The following theorem is a companion to Theorem 5.5.3.
