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What is the value of m if the vectors 2 i - j + k , i +2 j -3 k and 3 i +m j +5 k are coplanar?

Options

  1. A-2
  2. B2
  3. C-4
  4. D4

Correct answer

C. -4

Step-by-step solution

aligned & | array ccc 2 & -1 & 1 1 & 2 & -3 3 & m & 5 array |=0 & array l 2(10+3 m)+1(5+9)+1(m-6)=0 20+6 m+14+m-6=0 7 m+28=0 array & array l 7=-4 . array aligned

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