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Without expanding evaluate the following determinant: |2345686x9x12x|

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Question

Without expanding evaluate the following determinant:

`|(2, 3, 4),(5, 6, 8),(6x, 9x, 12x)|`

Sum
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Solution

Let D = `|(2, 3, 4),(5, 6, 8),(6x, 9x, 12x)|`

Taking (3x) common from R3, we get

D = `3x|(2, 3, 4),(5, 6, 8),(2, 3, 4)|`

= (3x)(0)    ...[∵ R1 and R3 are identical]

= 0

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Chapter 4: Determinants and Matrices - Exercise 4.2 [Page 67]

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