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AP EAMCET · Maths · Quadratic Equation

If one root of \(x^3-7 x^2+36=0\) is twice the other, then the sum of those two roots is

  1. A 6
  2. B 9
  3. C -9
  4. D 12
Verified Solution

Answer & Solution

Correct Answer

(B) 9

Step-by-step Solution

Detailed explanation

Let the roots be \( \alpha, 2\alpha, \beta \). \( \alpha + 2\alpha + \beta = 7 \Rightarrow 3\alpha + \beta = 7 \) \( \alpha(2\alpha) + (2\alpha)\beta + \beta\alpha = 0 \Rightarrow 2\alpha^2 + 3\alpha\beta = 0 \)…