Multiple choice

If $\alpha, \beta, \gamma$ be the roots of the equation $2x^3 + 3x^2 - 12x + 3 = 0$ and $A (\alpha, \beta, \gamma), B (\beta, \gamma, \alpha) C(\gamma, \alpha, \beta)$ represent vertices of a triangle ABC then the centroid of the triangle lies upon the line

  1. x = y = z

  2. x = 2y = 3z

  3. x = - 2y =3z

  4. x =y = - 2z

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A Correct answer
Explanation

The centroid of triangle ABC with vertices (alpha, beta, gamma), (beta, gamma, alpha), and (gamma, alpha, beta) is ((alpha+beta+gamma)/3, (beta+gamma+alpha)/3, (gamma+alpha+beta)/3). Since alpha+beta+gamma = -3/2 (from Vieta's formulas), the centroid is (-1/2, -1/2, -1/2). This point satisfies the line x = y = z.

AI explanation

Using the centroid formula, the x coordinate is (alpha + beta + gamma)/3, the y coordinate is (beta + gamma + alpha)/3, and the z coordinate is (gamma + alpha + beta)/3. Since the numerators are identical, the coordinates are equal, placing the centroid on the line x = y = z.