The eigenvalues of a 6x6 matrix as t runs back and forth between -100 and 100.

The matrix is ((1,2,3,4,5,t),(2,4,6,7,8,9),(9,6,3,1,2,1),(7,6,5,4,3,1), (0,3,72,3,7,4),(4,5,4,5,4,8)).