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The System of Equation X + Y + Z = 2, 3x − Y + 2z = 6 and 3x + Y + Z = −18 Has (A) a Unique Solution (B) No Solution (C) an Infinite Number of Solutions (D) Zero Solution as the Only Solution

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प्रश्न

The system of equation x + y + z = 2, 3x − y + 2z = 6 and 3x + y + z = −18 has

विकल्प

  • a unique solution

  • no solution

  • an infinite number of solutions

  • zero solution as the only solution

MCQ
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उत्तर

(a) a unique solution

The given system of equations can be written in matrix form as follows:
\[\begin{bmatrix}1 & 1 & 1 \\ 3 & - 1 & 2 \\ 3 & 1 & 1\end{bmatrix}\begin{bmatrix}x \\ y \\ z\end{bmatrix} = \begin{bmatrix}2 \\ 6 \\ - 18\end{bmatrix}\]
\[AX = B \]
Here, 
\[A = \begin{bmatrix}1 & 1 & 1 \\ 3 & - 1 & 2 \\ 3 & 1 & 1\end{bmatrix}, X = \begin{bmatrix}x \\ y \\ z\end{bmatrix}\text{ and }B = \begin{bmatrix}2 \\ 6 \\ - 18\end{bmatrix}\]
\[\left| A \right|=1 \left( - 1 - 2 \right) - 1\left( 3 - 6 \right) + 1\left( 3 + 3 \right)\]
\[ = - 3 + 3 + 6\]
\[ = 6\neq0\]
So, the given system of equations has a unique solution.

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  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
अध्याय 7: Solution of Simultaneous Linear Equations - Exercise 8.4 [पृष्ठ २१]

APPEARS IN

आर.डी. शर्मा Mathematics Volume 1 and 2 [English] Class 12
अध्याय 7 Solution of Simultaneous Linear Equations
Exercise 8.4 | Q 1 | पृष्ठ २१

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