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If Two of the Zeros of the Cubic Polynomial Ax3 + Bx2 + Cx + D Are Each Equal to Zero, Then the Third Zero is - Mathematics

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Question

If two of the zeros of the cubic polynomial ax3 + bx2 + cx + d are each equal to zero, then the third zero is

Options

  • \[\frac{- d}{a}\]
  • \[\frac{c}{a}\]
  • \[\frac{- b}{a}\]
  • \[\frac{b}{a}\]
MCQ

Solution

Let `alpha = 0, beta=0` and y be the zeros of the polynomial

f(x)= ax3 + bx2 + cx + d 

Therefore

`alpha + ß + y= (-text{coefficient of }X^2)/(text{coefficient of } x^3)`

`= -(b/a)`

`alpha+beta+y = -b/a`

`0+0+y = -b/a`

`y = - b/a`

`\text{The value of}  y - b/a`

Hence, the correct choice is `(c).`

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Chapter 2: Polynomials - Exercise 2.5 [Page 63]

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RD Sharma Mathematics [English] Class 10
Chapter 2 Polynomials
Exercise 2.5 | Q 21 | Page 63

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