Ответ:

-2x2+4x3=4x2-2x3

6x3=6x2

x3=x2

2x1-x2-x3(x3=x2)=4

2x1-x2-x2=4

2x1-2x2=4

x1-x2(x2=x3)=2

x1-x3=2

x1=x3+2

3x1(x3+2)-2x2-4x3(x2=x3)=11

3x3+6-2x3-4x3=11

6-3x3=11

x3=-5:3