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CUET · MATHS · PYQ PAPER 2025

If the points (-1,-1,2), (2, m, 5) and (3, 11, 6) are collinear, then m equals

  1. A 4
  2. B 8
  3. C 0
  4. D -2
Verified Solution

Answer & Solution

Correct Answer

(B) 8

Step-by-step Solution

Detailed explanation

\(\vec{AB} = \langle 2 - (-1), m - (-1), 5 - 2 \rangle = \langle 3, m+1, 3 \rangle\) \(\vec{BC} = \langle 3 - 2, 11 - m, 6 - 5 \rangle = \langle 1, 11-m, 1 \rangle\) For collinearity: \(\frac{3}{1} = \frac{m+1}{11-m}\) \(3(11-m) = m+1\) \(33 - 3m = m+1\) \(32 = 4m\) \(m = 8\)