Ex 12.2, 5 (ii) - Chapter 12 Class 8 Factorisation

Last updated at August 13, 2026 by

Ex 12.2, 5 (ii) - Factorise q^2 - 10q + 21 - Chapter 14 Class 8 NCERT - Ex 12.2

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Ex 12.2, 5 Factorise the following expressions. (ii) 𝑞^2 – 10q + 21𝑞^2 – 10q + 21 By middle term splitting = 𝑞^2−𝟑𝒒−𝟕𝒒+21 = (𝑞^2−3𝑞)−(7𝑞−21) = q (q − 3) − 7(q − 3) Taking (q − 3) common, = (q − 3) (q − 7) Splitting the middle term We need to find two numbers whose Sum = −10 Product = 21 So, we write −10q = −3q − 7q

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