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Examine the consistency of the system of equations. x + 3y = 5 2x + 6y = 8 - Mathematics

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प्रश्न

Examine the consistency of the system of equations.

x + 3y = 5

2x + 6y = 8

योग
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उत्तर

Let, A = `[(1,3),(2,6)]`, X = `[(x),(y)]`, B = `[(5),(8)]`

Then the given system of equations can be written as,

`[(1,3),(2,6)][(x),(y)] = [(5),(8)]`

Now, |A|

= `|(1,3),(2,6)|`

= 1 × 6 − 2 × 3

= 6 − 6

= 0

Cofactors of the elements of |A| are, respectively,

A11 = 6, A12 = −2, A21 = −3, A22 = 1

∴ adj A = `[(6,-2),(-3,1)] = [(6,-3),(-2,1)]`

⇒ (adj A)B = `[(6,-3),(-2,1)] [(5),(8)]`

= `[(30 - 24),(-10 + 8)]`

= `[(6),(-2)] ≠ 0`

|A| = 0 and (adj A)B ≠ 0

Therefore, the given system of equations is inconsistent.

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अध्याय 4: Determinants - Exercise 4.6 [पृष्ठ १३६]

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एनसीईआरटी Mathematics Part 1 and 2 [English] Class 12
अध्याय 4 Determinants
Exercise 4.6 | Q 3 | पृष्ठ १३६

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