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
MCQs from NCERT Exemplar
Last updated at April 16, 2024 by Teachoo
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)