question_answer 4)

If  then show that |3A| = 27 |A|.  

Answer:

.       Multiply it by 3, we get                   Expanding along C1, we get             = 3 (36 ? 0) = 108             Expanding along C1, we get             = 4 ? 0 = 4             Multiply it by 27, we get       27 |A| = 27 × 4 = 108                       ?.. (2)       From (1) and (2), we have       |3A| = 27 |A|