Engineering Board Exam Reviewer · Cramer's Rule and Linear Systems · medium

For what value of k does x+2y=0, 3x+ky=0 have nontrivial solutions?

1. 3
2. -6
3. 2
4. 6

Answer

D. 6

Solution

A homogeneous system has nontrivial solutions only when D=0: vmatrix1&2\3&k vmatrix=k-6=0 k=6.

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