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If x = – 4 is a root of Δ = |x231x132x| = 0, then find the other two roots. - Mathematics

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प्रश्न

If x = – 4 is a root of Δ = `|(x, 2, 3),(1, x, 1),(3, 2, x)|` = 0, then find the other two roots.

योग
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उत्तर

Applying R1 → (R1 + R2 + R3), we get

`|(x + 4, x + 4, x + 4),(1, x, 1),(3, 2, x)|`

Taking (x + 4) common from R1, we get

Δ = `(x + 4) |(1, 1, 1),(1, x, 1),(3, 2, x)|`

Applying C2 → C2 – C1, C3 → C3 – C1 , we get

Δ = `(x + 4)|(1, 0, 0),(1, x - 1, 0),(3, -1, x - 3)|`

Expanding along R1,

∆ = (x + 4)[(x – 1)(x – 3) – 0].

Thus, ∆ = 0 implies x = – 4, 1, 3.

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अध्याय 4: Determinants - Solved Examples [पृष्ठ ७१]

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एनसीईआरटी एक्झांप्लर Mathematics [English] Class 12
अध्याय 4 Determinants
Solved Examples | Q 7 | पृष्ठ ७१

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