Determinant zero for a non-zero solution of homogeneous linear equations
This type of question, asked 2 times: 26 Apr 2025 S1, 15 May 2026 S2. All 2 questions below, oldest first.
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Question 1
26 Apr 2025 S1
130
If a=λxi^+yj^+4zk^, b=yi^+xj^+3yk^ and c=−zi^−2zj^−(λ+1)xk^ are the sides of the triangle ABC, where x,y,z are not all zero, such that a+b−c=0, then the value of λ is
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Question 2
15 May 2026 S2
73
If the planes ax=y+z, by=z+x, cz=x+y pass through a common line, then the value of (a+b+c−abc)=⋯