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If alpha, beta, gamma are roots of the e...

If `alpha, beta, gamma` are roots of the equation `x^(3) + px^(2) + qx + r = 0`, then `(alpha + beta) (beta + gamma)(gamma + alpha)` =

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To find the value of \((\alpha + \beta)(\beta + \gamma)(\gamma + \alpha)\) given that \(\alpha, \beta, \gamma\) are the roots of the polynomial equation \(x^3 + px^2 + qx + r = 0\), we can follow these steps: ### Step 1: Identify the roots and coefficients The roots of the polynomial are \(\alpha, \beta, \gamma\) and the polynomial can be expressed in the standard form \(ax^3 + bx^2 + cx + d = 0\). Here, we have: - \(a = 1\) - \(b = p\) - \(c = q\) - \(d = r\) ### Step 2: Use Vieta's formulas From Vieta's formulas, we know: 1. \(\alpha + \beta + \gamma = -\frac{b}{a} = -p\) 2. \(\alpha \beta + \beta \gamma + \gamma \alpha = \frac{c}{a} = q\) 3. \(\alpha \beta \gamma = -\frac{d}{a} = -r\) ### Step 3: Expand the expression We need to expand \((\alpha + \beta)(\beta + \gamma)(\gamma + \alpha)\): \[ (\alpha + \beta)(\beta + \gamma)(\gamma + \alpha) = (\alpha + \beta + \gamma)(\alpha \beta + \beta \gamma + \gamma \alpha) - \alpha \beta \gamma \] Substituting the values from Vieta's formulas: - \(\alpha + \beta + \gamma = -p\) - \(\alpha \beta + \beta \gamma + \gamma \alpha = q\) - \(\alpha \beta \gamma = -r\) ### Step 4: Substitute the values Now substituting these values into the expanded expression: \[ (\alpha + \beta)(\beta + \gamma)(\gamma + \alpha) = (-p)(q) - (-r) \] This simplifies to: \[ -pq + r \] ### Step 5: Final result Thus, the value of \((\alpha + \beta)(\beta + \gamma)(\gamma + \alpha)\) is: \[ r - pq \] ### Conclusion The final answer is: \[ \boxed{r - pq} \]
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