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

Sum

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

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

#### 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