1. [10] Let A = 2 4 a b c d e

1. [10] Let A = 2 4 a b c d e f g h i 3 5, B = 2 4 d + 5g e+ 5h f+ 5i a − 2g b− 2h c− 2i g h i 3 5, C = 2 4 2g 2h 2i 3d 3e 3f −1a −1b −1c 3 5. Suppose that det A = 5. Find det B = , det C = , and det (AC) =