Ex 2.4, 1 (iii) - Chapter 2 Class 9 Polynomials

Last updated at August 14, 2026 by

Ex 2.4, 1 (iii) - Use suitable identities to find: (3x + 4) (3x - 5) - Ex 2.4

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Ex 2.4, 1 Use suitable identities to find the following products: (iii) (3x + 4) (3x - 5) (3x + 4) (3x – 5) = 3 (𝑥+ 4/3) 3(𝑥− 5/3) = (9) (𝑥+ 4/3) (𝑥− 5/3) Using (x + a) (x + b) = x2 + (a + b) x + ab, Where a = 4/3 , b = (−5)/3 = 9 [𝑥2+(4/3+(−5)/3)𝑥+(4/3)(− 5/3)] = 9 [𝑥2 +((4 − 5))/3 𝑥 −20/9] = 9 [𝑥2 − 1/3 𝑥 −20/9] = 9(𝑥2) −9(1/3)𝑥 −9(20/9) = 9x2 – 3x – 20

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