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Consider the following system of linear equations:

2x - y + z = 1
3x - 3y + 4z = 6
x - 2y + 3z = 4

This system of linear equations has

  • A.no solution.
  • B.one solution.
  • C.two solutions.
  • D.three solutions.

Answer: A

The system has no solution.

Subtract the first equation from the second:

\[ \begin{aligned} (3x - 3y + 4z) - (2x - y + z) &= 6 - 1 \\ x - 2y + 3z &= 5 \end{aligned} \]

But the third equation says \(x - 2y + 3z = 4\). The same expression cannot equal both 5 and 4, so the equations are inconsistent. In matrix terms, the coefficient matrix has rank 2 while the augmented matrix has rank 3.

A consistent system with a rank-deficient matrix would have infinitely many solutions, not exactly two or three, and a unique solution would need the coefficient matrix to be non-singular, which it is not here.

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