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QJEEM20Mab1be: JEE Main 2020 Mathematics - Class 12 JEEM20Mab1be Solution: If the system of linear equations x + y + 3z = 0 x + 3y + k 2 z …

If the system of linear equations
x + y + 3z = 0
x + 3y + k2z = 0
3x + y + 3z = 0
has a non-zero solution (x, y, z) for some k ∈ R, then x + (yz) is equal to :

Multiple Choice Options

  • A 9
  • B 3
  • C -9
  • D -3

Step-by-Step Verified Solution

x + y + 3z = 0 .....(i)
x + 3y + k2z = 0 .........(ii)
3x + y + 3z = 0 ......(iii)

|11313k2313| = 0

⇒ 9 + 3 + 3k2 – 27 – k2 – 3 = 0

⇒ k2 = 9

Perform (i) – (iii),

–2x = 0 ⇒ x = 0

Now from (i), y + 3z = 0

⇒ yz=−3

∴ x + (yz) = -3

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