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AP EAMCET · Maths · Quadratic Equation

If the sum of two roots of the equation \(x^3-2 p x^2+3 q x-4 r=0\) is zero, then the value of \(r\) is

  1. A \(\frac{3 p q}{2}\)
  2. B \(\frac{3 p q}{4}\)
  3. C \(p q\)
  4. D \(2 p q\)
Verified Solution

Answer & Solution

Correct Answer

(A) \(\frac{3 p q}{2}\)

Step-by-step Solution

Detailed explanation

Let the two roots of equation is \(m,-m\). Now, sum of three roots \(=2 p\) Hence, third root will be \(2 p\). Now, \(m \times(-m)+m \times(2 p)+(-m) \times 2 p=3 q\) \[ \Rightarrow \quad-m^2=3 q \] Now, \(\quad m \times(-n) \times 2 p=4 r\)…