Given that two of the zeroes of the cubic polynomial ax 3

 + bx 2 + cx + d are 0, the third zero is

(a) (-b)/a        (b) b/a  (c) c/a    (d) -d/a

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Question 2 Given that two of the zeroes of the cubic polynomial ax3 + bx2 + cx + d are 0, the third zero is (a) (−𝑏)/𝑎 (b) 𝑏/𝑎 (c) 𝑐/𝑎 (d) −𝑑/𝑎 Let p(x) = ax3 + bx2 + cx + d Given that two zeroes are 0 ∴ 𝜶 = 0, 𝜷 = 0 and we need to find 𝜸 We know that Sum of zeroes = (−𝒃)/𝒂 𝜶 + 𝜷 + 𝜸 = (−𝑏)/𝑎 0 + 0 + 𝜸 = (−𝑏)/𝑎 𝜸 = (−𝑏)/𝑎 𝜶 + 𝛽 + 𝛾 = (−𝑏)/𝑎 0 + 0 + 𝛾 = (−𝑏)/𝑎 𝜸 = (−𝒃)/𝒂 Thus, the third zero is (−𝑏)/𝑎 So, the correct answer is (A)

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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 13 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.