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If one of the zeroes of cubic polynomial x3+ px2+ q+
r is - 1, then the product of the other two zeroes is a) p q 1 b) p-q-1 c) q-p 1 d) q-p-1?
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If one of the zeroes of cubic polynomial x3+ px2+ q+r is - 1, then the...
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If one of the zeroes of cubic polynomial x3+ px2+ q+r is - 1, then the...
Explanation:
A cubic polynomial is of the form ax^3 + bx^2 + cx + d where a, b, c, and d are constants.

Let α, β, and γ be the zeroes of the cubic polynomial x^3 + px^2 + qx + r. Then, by the factor theorem, we have:


  • x^3 + px^2 + qx + r = (x - α)(x - β)(x - γ)


Given that one of the zeroes is -1, we can substitute this value in the equation above to get:


  • 1 - p + q + r = 0


Therefore, we have:


  • p - q - r = 1


Let the other two zeroes be α and β. Then, by Vieta's formulas, we have:


  • αβγ = -r

  • α + β + γ = -p

  • αβ + βγ + γα = q


Since one of the zeroes is -1, we can rewrite the above equations as:


  • αβ = -r/γ

  • α + β + γ = -p

  • αβ + βγ + γα = q

  • αβγ = -r

  • αβγ = γ(-r/γ) = -rγ

  • αβ + βγ + γα = αβ + γ(-1) + α(-1) = αβ - γ - α


Substituting the values of αβγ and αβ + βγ + γα in the equation αβγ = -r, we get:


  • (αβ - γ - α)γ = -r

  • αβγ - γ^2 - αγ = -r

  • -r - γ^2 - αγ = -r

  • γ^2 + αγ = 0

  • γ(γ + α) = 0


Since γ = -1, we have:


  • αβ - γ - α = αβ + 1 + α = α(α + β + 1) = -r/γ = r


Substituting α + β = -γ - p = 1 - p and simplifying, we get:


  • αβ = r - α - β = r - (1 - p) = p - r + 1


Therefore, the product of the other two zeroes is p - r + 1.

Hence, the answer is option (d) q - p - 1.
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If one of the zeroes of cubic polynomial x3+ px2+ q+r is - 1, then the product of the other two zeroes is a) p q 1 b) p-q-1 c) q-p 1 d) q-p-1?
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If one of the zeroes of cubic polynomial x3+ px2+ q+r is - 1, then the product of the other two zeroes is a) p q 1 b) p-q-1 c) q-p 1 d) q-p-1? for Class 10 2024 is part of Class 10 preparation. The Question and answers have been prepared according to the Class 10 exam syllabus. Information about If one of the zeroes of cubic polynomial x3+ px2+ q+r is - 1, then the product of the other two zeroes is a) p q 1 b) p-q-1 c) q-p 1 d) q-p-1? covers all topics & solutions for Class 10 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for If one of the zeroes of cubic polynomial x3+ px2+ q+r is - 1, then the product of the other two zeroes is a) p q 1 b) p-q-1 c) q-p 1 d) q-p-1?.
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