Answer
$( -1, 1, 1)$
Work Step by Step
Write the augmented matrix and,
using row transformations arrive at the reduced row echelon form.
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It was suggested to use technology for some problems...
Syntax for matrix input:
A:={{-0.5, 0.5, 0.5, 1.5},{4.2, 2.1, 2.1, 0},{ 0.2, 0, 0.2, 0}}
In the input box, begin typing "Red..."
select the function:
ReducedRowEchelonForm(A)
(see screenshot)
Solution: $( -1, 1, 1)$