Question 26
Matrices and DeterminantsFind the value of k if
| −2 1 1 |
| 2 1 k | = 23
| 1 2 −1 |
- A.1
- B.2
- C.3
- D.16/5
Show the answer and explanation
Answer: D (16/5)
Explanation
Expand along the top row: −2(−1 − 2k) − 1(−2 − k) + 1(4 − 1) = 7 + 5k. So 7 + 5k = 23 and k = 16/5.