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AP EAMCET · Maths · Quadratic Equation

If the sum of the cubes of the roots of the equation \(x^3-a x^2+b x-c=0\) is zero, then \(a^3+3 c=\)

  1. A \(-2 a b\)
  2. B \(2 \mathrm{ab}\)
  3. C \(-3 a b\)
  4. D \(3 a b\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(3 a b\)

Step-by-step Solution

Detailed explanation

Given: \(x^3-a x^2+b x-c=0 ...(i)\) Let \(\alpha, \beta \& \gamma\) are the roots equation (i), we get \(\begin{aligned} & \alpha+\beta+\gamma=a \\ & \alpha \beta+\beta \gamma+\gamma \alpha=b \\ & \alpha \beta \gamma=c \end{aligned}\) Also, given: \(\alpha^3+\beta^3+\gamma^3=0\)…