Calculate the determinant.
#1. \(\begin{vmatrix} -9 & -5\\1 & -6\\\end{vmatrix}\)
#2. \(\begin{vmatrix} 1 & 6\\10 & -8\\\end{vmatrix}\)
#3. \(\begin{vmatrix} -10 & -10 & -10\\5 & -8 & -21\\10 & 9 & 8\\\end{vmatrix}\)
Find the inverse of the given matrix or state that it is singular.
#4. \(\begin{bmatrix} -5 & -1\\4 & 2\\\end{bmatrix}\)
#5. \(\begin{bmatrix} 7 & -28\\6 & -24\\\end{bmatrix}\)
#6. \(\begin{bmatrix} 2 & -6 & -9\\-4 & -2 & -1\\-7 & -2 & -3\\\end{bmatrix}\)