If the system of linear equations x + k y + 3 z = 0 3 x + k y - 2 z = 0 2 x + 4 y - 3 z = 0 has a non-zero…

If the system of linear equations

x+ky+3z=0
3x+ky-2z=0
2x+4y-3z=0

has a non-zero solution x, y, z, then xzy2 is equal to:

  1. 30
  2. -10
  3. 10
  4. -30

Solution

1k33k-224-3=0

-3k+8-3-3k-12+2-5k=0

-4k+44=0  k=11

x+11y+3z=0   ...1

3x+11y-2z=0   ...2

2x+4y-3z=0   ...3

On solving equations1 & 2, we get

2x-5z=0

x=5z2

Put it in equation 3, we get

2z+4y=0

z=-2y

xzy2=-2y×-5yy2=10

Asked in: JEE Main 2018 (08 Apr)

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