4x1-x2-5x3=1
x1+x2-2x3=6 |•(-3)
3x1-2x2-6x3=-2
-3x1-3x2+6x3=-18
3x1-2x2-6x3=-2
___________"+"
0-5x2+0=-20
5x2=20=>x2=10
4x1-x2-5x3=1
x1+x2-2x3=6
4x1-5x3=11
x1-2x3=-4 |(-4)
4x1-5x3=11
-4x1+8x3=16
__________"+"
0+3x3=27<=>3x3=27=>x3=9
x1-2x3=-4<=>x1=-4+2•9=-4+18=14
x1=14
x2=10
x3=9
