One way to do this is to use the Gauss-Jordan Method.
Replace the given equations with an augmented matrix
Initial Augmented Matrix:
#(
(color(white)("XXX")x,color(white)("XXX")y,color(white)("XXXX")z,color(white)("XXX")=),
(color(white)("XXX")2.0,color(white)("XXXX")-3.0,color(white)("XXX")1.0,color(white)("XXXX")-2.0),
(color(white)("XXX")1.0,color(white)("XXXX")-6.0,color(white)("XXX")3.0,color(white)("XXXX")-2.0),
(color(white)("XXX")3.0,color(white)("XXX")3.0,color(white)("XXXX")-2.0,color(white)("XXX")2.0)
)#
Pivot Row: 1 Pivot Column: 1
pivot Row reduced:
#(
(color(white)("XXX")1.0,color(white)("XXXX")-1.5,color(white)("XXX")0.5,color(white)("XXXX")-1.0),
(color(white)("XXX")1.0,color(white)("XXXX")-6.0,color(white)("XXX")3.0,color(white)("XXXX")-2.0),
(color(white)("XXX")3.0,color(white)("XXX")3.0,color(white)("XXXX")-2.0,color(white)("XXX")2.0)
)#
Non-pivot rows reduced for pivot column
#(
(color(white)("XXX")1.0,color(white)("XXXX")-1.5,color(white)("XXX")0.5,color(white)("XXXX")-1.0),
(color(white)("XXX")0.0,color(white)("XXXX")-4.5,color(white)("XXX")2.5,color(white)("XXXX")-1.0),
(color(white)("XXX")0.0,color(white)("XXX")7.5,color(white)("XXXX")-3.5,color(white)("XXX")5.0)
)#
Pivot Row: 2 Pivot Column: 2
pivot Row reduced:
#(
(color(white)("XXX")1.0,color(white)("XXXX")-1.5,color(white)("XXX")0.5,color(white)("XXXX")-1.0),
(color(white)("XXX")0.0,color(white)("XXX")1.0,color(white)("XXXX")-0.556,color(white)("XXX")0.222),
(color(white)("XXX")0.0,color(white)("XXX")7.5,color(white)("XXXX")-3.5,color(white)("XXX")5.0),
(color(white)("XXX")x,color(white)("XXX")y,color(white)("XXXX")-z,color(white)("XXX")=)
)#
Non-pivot rows reduced for pivot column
#(
(color(white)("XXX")1.0,color(white)("XXX")0.0,color(white)("XXXX")-0.333,color(white)("XXXX")-0.667),
(color(white)("XXX")0.0,color(white)("XXX")1.0,color(white)("XXXX")-0.556,color(white)("XXX")0.222),
(color(white)("XXX")0.0,color(white)("XXX")0.0,color(white)("XXX")0.667,color(white)("XXX")3.333)
)#
Pivot Row: 3 Pivot Column: 3
pivot Row reduced:
#(
(color(white)("XXX")1.0,color(white)("XXX")0.0,color(white)("XXXX")-0.333,color(white)("XXXX")-0.667),
(color(white)("XXX")0.0,color(white)("XXX")1.0,color(white)("XXXX")-0.556,color(white)("XXX")0.222),
(color(white)("XXX")0.0,color(white)("XXX")0.0,color(white)("XXX")1.0,color(white)("XXX")5.0)
)#
Non-pivot rows reduced for pivot column
#(
(color(white)("XXX")1.0,color(white)("XXX")0.0,color(white)("XXX")0.0,color(white)("XXX")1.0),
(color(white)("XXX")0.0,color(white)("XXX")1.0,color(white)("XXX")0.0,color(white)("XXX")3.0),
(color(white)("XXX")0.0,color(white)("XXX")0.0,color(white)("XXX")1.0,color(white)("XXX")5.0),
(color(white)("XXX")x,color(white)("XXX")y,color(white)("XXXX")z,color(white)("XXX")=)
)#