CBSE Class 12 Mathematics 2026 Main Paper 65/4/2 · Q273 Marksmatrix_polynomials
CBSE Class 12 Mathematics 2026 Main Paper 65/4/2 · Question 27 (Matrices)
For A=[[1,2,2],[2,1,2],[2,2,1]], compute A²−4A−5I.
✅ Step-by-Step Solution
Final Answer: Zero matrix.
- Multiplication gives A²=[[9,8,8],[8,9,8],[8,8,9]].
- Subtracting 4A leaves 5 on the diagonal and zero elsewhere.
- Subtract 5I to obtain the zero matrix.
📋 CBSE Stepwise Marking Scheme
- [0.5 marks] Multiplication gives A²=[[9,8,8],[8,9,8],[8,8,9]].
- [2 marks] Subtracting 4A leaves 5 on the diagonal and zero elsewhere.
- [0.5 marks] Subtract 5I to obtain the zero matrix.
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