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Find the zeroes of the quadratic polynomial x 2 − 3x − 10 and verify the relationship between the zeroes and coefficient.

Question 27 - CBSE Class 10 Sample Paper for 2020 Boards - Maths Basic

Question 27 - CBSE Class 10 Sample Paper for 2020 Boards - Maths Basic - Part 2
Question 27 - CBSE Class 10 Sample Paper for 2020 Boards - Maths Basic - Part 3

Note : This is similar to Ex 2.2, 1 of NCERT – Chapter 2 Class 10

Check the answer here https://www.teachoo.com/1489/494/Ex-2.2--1---Find-zeroes-of-following-quadratic-polynomials/category/Ex-2.2/

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Transcript

Question 27 Find the zeroes of the quadratic polynomial x2 − 3x − 10 and verify the relationship between the zeroes and coefficient. Let p(x) = x2 − 3x − 10 Finding zeroes by putting p(x) = 0 x2 – 3x – 10 = 0 We find roots using splitting the middle term method x2 – 5x + 2x – 10 = 0 x(x – 5) + 2(x – 5) = 0 (x + 2) (x – 5) = 0 So, x = –2, 5 Splitting the middle term method We need to find two numbers whose Sum = –3 Product = 1 × –10 = –10 So, zeroes are –2 and 5 Now, lets verify the relationship p(x) = x2 − 3x − 10 Sum of zeroes Sum of zeroes = − (𝐶𝑜𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑡 𝑜𝑓 𝑥)/(𝐶𝑜𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑡 𝑜𝑓 𝑥2) LHS –2 + 5 = 3 RHS (−𝑏)/𝑎 = (−(−3))/1 = 3 Product of zeroes Product of zeroes = (𝐶𝑜𝑛𝑠𝑡𝑎𝑛𝑡 𝑡𝑒𝑟𝑚)/(𝐶𝑜𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑡 𝑜𝑓 𝑥2) LHS –2 × 5 = –10 RHS 𝑐/𝑎 = (−10)/1 = –10 Since, L.H.S = R.H.S Hence relationship between zeroes & coefficient is verified

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Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.