The following matrix is is row-echelon form and represent a linear system. Solve the system using backward substitution. Write the solution as an ordered triple. [[ 1 1 -1 5][ 0 1 -1 2][ 0 0 1 1]]

z=1 
y-z=2
y-1=2
y=3 
x+y-z=5
x+3-1=5
x=3 
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