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Find k if the following matrix is singular: [73-2k]

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Question

Find k if the following matrix is singular:

`[(7, 3),(-2, "k")]`

Sum
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Solution

Let A = `[(7, 3),(-2, "k")]`

Since A is a singular matrix,
IAI = 0

∴ `|(7, 3),(-2, "k")|` = 0

∴ 7k – (– 6) = 0

∴ 7k + 6 = 0

∴ 7k = – 6

∴ k = `(-6)/7`.

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

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