Question 28
Matrices and DeterminantsFind the value of x for which the determinant |x −1 −2; 2 1 0; −x 0 4| = 0 (rows separated by semicolons)
- A.0
- B.2
- C.−4
- D.−8
Show the answer and explanation
Answer: C (−4)
Explanation
Expanding along the first row: x(4) + 1(8) − 2(0 + x) = 2x + 8 = 0, so x = −4.