How many numbers greater than 5000 can be formed using the digits 3, 4, 5, 6, and 7 without repetition of digits? How many of these are even?
Why does the matrix [math] M = \begin{bmatrix}1 & 2  & 3\\4 & 5 & 6\\7 & 8 & 9\end{bmatrix} [/math] have a [math]0[/math] determinant?