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Ex 2.2, 1 - Find zeroes of following quadratic polynomials - Ex 2.2

Ex 2.2, 1 - Chapter 2 Class 10 Polynomials - Part 2


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Ex 2.2, 1(i) Find the zeroes of the following quadratic polynomials and verify the relationship between the zeroes and the coefficients. x2 – 2x – 8 Let p(x) = x2 – 2x – 8 Zero of the polynomial is the value of x where p(x) = 0 Putting p(x) = 0 x2 – 2x – 8 = 0 We find roots using splitting the middle term method x2 – 4x + 2x – 8 = 0 x(x – 4) + 2(x – 4) = 0 (x + 2)(x − 4) = 0 So x = −2, 4 Therefore, α = – 2 & β = 4 are the zeroes of the polynomial p(x) = x2 – 2x – 8 = 1x2 – 2x – 8 Comparing with ax2 + bx + c So a = 1 , We verify Sum of zeroes = − (𝐶𝑜𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑡 𝑜𝑓 𝑥)/(𝐶𝑜𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑡 𝑜𝑓 𝑥2) i.e. α + β = - 𝑏/𝑎 Since, L.H.S = R.H.S Hence relationship between zeroes & coefficient is verified

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Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 12 years. He provides courses for Maths and Science at Teachoo.