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JEE Mains · Maths · STD 12 - 3 and 4 . metrices and determinant

The number of real values of \(\lambda \) for which the system of linear equations \(2x + 4y - \lambda  z = 0\) ;\(4x + \lambda y + 2z = 0\) ; \(\lambda x + 2y+ 2z = 0\) has infinitely many solutions, is

  1. A \(0\)
  2. B \(1\)
  3. C \(2\)
  4. D \(3\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(1\)

Step-by-step Solution

Detailed explanation

Since the given system of linear equations has infinitely many solutions. \(\therefore \begin{array}{*{20}{c}} 2&4&{ - \lambda }\\ 4&\lambda &2\\ \lambda &2&2 \end{array} = 0\) \( \Rightarrow {\lambda ^3} + 4\lambda - 40 = 0\) \(\lambda \) has only \(1\) real root.