Verified Solution • 2025–26 Session moderate

QJEEM21Ma6fbe: JEE Main 2021 Mathematics - Class 12 JEEM21Ma6fbe Solution: Let the system of linear equations 4x + λ y + 2z = 0 2x − y + z …

Let the system of linear equations

4x + λy + 2z = 0

2x − y + z = 0

μx + 2y + 3z = 0, λ, μ∈R.

has a non-trivial solution. Then which of the following is true?

Multiple Choice Options

  • A μ = 6, λ∈R
  • B λ = 3, μ∈R
  • C μ = −6, λ∈R
  • D λ = 2, μ∈R

Step-by-Step Verified Solution

Given, system of linear equations

4x + λy + 2z = 0

2x − y + z = 0

μx + 2y + 3z = 0

For non-trivial solution, Δ = 0

|4λ22−11μ23|=0

⇒4(−3−2)−λ(6−μ)+2(4+μ)=0

⇒−λ(6−μ)−2(6−μ)=0

⇒(6−μ)(λ+2)=0

⇒λ=−2 and μ∈R or μ = 6 and λ∈R.

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