Determinants
NCERT Class 12
CBSE
Grade 12
Question:
Solve system of linear equations using matrix method: $x - y + 2z = 7, 34x + y - 3z = -5, 2x + 5y + 3z = 0$.
Step-by-Step Solution
$|A| = 59
eq 0$. Cofactor inverse $A^{-1} = \dfrac{1}{59} \begin{bmatrix} 18 & 13 & 1 \\ -15 & -1 & 9 \\ 13 & -7 & 4 \end{bmatrix}$. [1.5 Marks]
$X = A^{-1} B \Rightarrow x = 2, y = -1, z = 1$. [1.5 Marks]
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🎯 Official CBSE Marking Scheme:
Evaluating $|A| = 59$ and matrix inverse $A^{-1}$: 1.5 Marks
Solving variable vector $X = A^{-1}B$: 1.5 Marks
Correct Answer:
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