Once again, math

[wallwalker]

Ah, Linear Algebra. The type of mathematics where it is not a stretch to work the same problem six times and get six different answers, none of which match the solution in the book, while only using simple arithmetic.

(Why would anyone assign a 4x4 determinant for students to do without matrix calculators or computers? Who does that anymore? Even the book acknowledges that 3x3 is the practical limit!)