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If alpha, beta, gamma are the zeros of ...

If `alpha, beta, gamma` are the zeros of the polynomial ` x^(3)-6x^(2) -x+ 30` then `(alpha beta+beta gamma + gamma alpha)`= ?

A

` -1`

B

1

C

`-5`

D

30

Text Solution

AI Generated Solution

The correct Answer is:
To find the value of \( \alpha \beta + \beta \gamma + \gamma \alpha \) for the polynomial \( x^3 - 6x^2 - x + 30 \), we can use Vieta's formulas. Vieta's formulas relate the coefficients of a polynomial to sums and products of its roots (zeros). ### Step-by-Step Solution: 1. **Identify the polynomial and its coefficients**: The given polynomial is \( x^3 - 6x^2 - x + 30 \). Here, the coefficients are: - \( a = 1 \) (coefficient of \( x^3 \)) - \( b = -6 \) (coefficient of \( x^2 \)) - \( c = -1 \) (coefficient of \( x \)) - \( d = 30 \) (constant term) 2. **Use Vieta's formulas**: According to Vieta's formulas, for a cubic polynomial \( ax^3 + bx^2 + cx + d = 0 \): - The sum of the roots \( \alpha + \beta + \gamma = -\frac{b}{a} \) - The sum of the products of the roots taken two at a time \( \alpha\beta + \beta\gamma + \gamma\alpha = \frac{c}{a} \) - The product of the roots \( \alpha\beta\gamma = -\frac{d}{a} \) 3. **Calculate \( \alpha\beta + \beta\gamma + \gamma\alpha \)**: From Vieta's formulas, we have: \[ \alpha\beta + \beta\gamma + \gamma\alpha = \frac{c}{a} = \frac{-1}{1} = -1 \] 4. **Final Answer**: Therefore, the value of \( \alpha\beta + \beta\gamma + \gamma\alpha \) is \( -1 \).

To find the value of \( \alpha \beta + \beta \gamma + \gamma \alpha \) for the polynomial \( x^3 - 6x^2 - x + 30 \), we can use Vieta's formulas. Vieta's formulas relate the coefficients of a polynomial to sums and products of its roots (zeros). ### Step-by-Step Solution: 1. **Identify the polynomial and its coefficients**: The given polynomial is \( x^3 - 6x^2 - x + 30 \). Here, the coefficients are: - \( a = 1 \) (coefficient of \( x^3 \)) ...
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Knowledge Check

  • If alpha, beta , gamma are the zeros of the polynomial x^(3)-6x^(2)-x+30 then the value of (alpha beta+beta gamma+gamma alpha) is

    A
    `-1 `
    B
    1
    C
    `-5`
    D
    30
  • If alpha, beta, gamma are the zeros of the polynomial 2x^(3)+ x^(2) - 13 x+ 6 then alpha beta gamma = ?

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    ` -3`
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    D
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    B
    `x^(3)+3x^(2)+10x-24`
    C
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    D
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