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- x - y -2z = 9, (1)
-2x -2y - z = 1, (2)
- x - y + z = -10. (3)
Distract equation (1) from equatin (3). You will get
3z = -10 -9 = -19. (4)
Now multiply equation (3) by 2 and then distract the equation (2). You will get
3z = 2*(-10) - 1 = -20 -1 = -21. (5)
You have two equations for z, (4) and (5), and they are inconsistent.
Hence, the original system is inconsistent.
Answer. This system has no solutions.
By the way, the determinant of the system is equal to zero.
