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Find the root of the following quadratic equations by the factorisation method: 21x2-2x+121 = 0 - Mathematics

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Sum

Find the root of the following quadratic equations by the factorisation method:

`21x^2 - 2x + 1/21` = 0

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Solution

Given equation is `21x^2 - 2x + 1/21` = 0

On multiplying by 21 on both sides, we get

`441x^2 - 42x + 1` = 0

`441x^2 - (21x + 21x) + 1` = 0   ....[By splitting the middle term]

⇒ `44x^2 - 21x - 21x + 1` = 0

⇒ `21x(21x - 1) - 1(21x - 1)` = 0

⇒ `(21x - 1)(21x - 1)` = 0

Now `21x - 1` = 0

⇒ `x = 1/21` and `21x - 1` = 0

∴ `x = 1/21`

Hence the roots of the equation `441x^2 - 42x + 1` = 0 are `1/21` and `1/21`.

Concept: Solutions of Quadratic Equations by Factorization
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APPEARS IN

NCERT Mathematics Exemplar Class 10
Chapter 4 Quadatric Euation
Exercise 4.3 | Q 2.(v) | Page 40
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