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Find k if the following matrix is singular: [k-1233121-24] - Mathematics and Statistics

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Question

Find k if the following matrix is singular:

`[("k" - 1, 2, 3),(3, 1, 2),(1, -2, 4)]`

Sum
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Solution

Let C = `[("k" - 1, 2, 3),(3, 1, 2),(1, -2, 4)]`

Since C is a singular matrix, ICI = 0

∴ `|("k" - 1, 2, 3),(3, 1, 2),(1, -2, 4)|` = 0

∴ (k – 1)(4 + 4) – 2(12 – 2) + 3( – 6 – 1) = 0

∴ 8k – 8 – 20 – 21 = 0

∴ 8k = 49

∴ k = `49/8`

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Chapter 4: Determinants and Matrices - Exercise 4.4 [Page 83]

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Balbharati Mathematics and Statistics 1 (Arts and Science) [English] Standard 11 Maharashtra State Board
Chapter 4 Determinants and Matrices
Exercise 4.4 | Q 4. (iii) | Page 83

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