ExamBro
ExamBro
TS EAMCET · Maths · Quadratic Equation

Two roots of the cubic \(x^3 + 3x^2 + kx = 0\) the value of k is 12 = 0 are real and unequal but have the same absolute value. Then

  1. A \(4\)
  2. B \(-4\)
  3. C \(6\)
  4. D \(-9\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(-4\)

Step-by-step Solution

Detailed explanation

\begin{align*} &\text{Let the roots be } r, -r, \text{ and } t. \text{ Hence, } r - r + t = -3 \Rightarrow t = -3. \\ &\text{Now, the product of the roots is } (r)(-r)(t) = 12. \\ &\Rightarrow -r^2 \cdot (-3) = 12. \\ &\Rightarrow r^2 = 4. \\ &\text{Hence, the roots are } 2, -2,…