This question is similar to CBSE Class 10 Sample Paper for 2021 Boards - Maths Standard

 

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Transcript

Question 8 A quadratic polynomial having zeroes −√(5/2) and √(5/2) is (A)〖 𝑥〗^2−5√2 𝑥+1 (B) 8𝑥^2−20 (C) 15𝑥^2−6 (D) 𝑥^2−2√5 𝑥−1Given Zeros −√(5/2) and √(5/2) . So, Sum of Zeroes = −√(5/2) + √(5/2) = 0 Product of Zeroes = −√(5/2) × √(5/2) = (−√5 × √5)/(√2 × √2) = (−𝟓)/𝟐 The Required polynomial is p(x) = x2 − (Sum of Zeroes)x + Product of Zeroes = x2 − 0x − 5/2 = x2 − 𝟓/𝟐 Now, our options are (A)〖 𝑥〗^2−5√2 𝑥+1 (B) 8𝑥^2−20 (C) 15𝑥^2−6 (D) 𝑥^2−2√5 𝑥− 1 Since there is no x term, options (a) and (d) are eliminated For B, let’s multiply our equation by 8 p(x) = 8 × (x2 − 𝟓/𝟐) = 8x2 − 8 × 𝟓/𝟐 = 8x2 − 20 Since this matches with option (b) So, the correct answer is (B)

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Davneet Singh

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.