Let \( f(z) = \dfrac{1}{z^2 + 6z + 9} \) defined in the complex plane. The integral \( \oint_{c} f(z) \, dz \) over the contour of a circle \( c \) with center at the origin and unit radius is \(\underline{\hspace{2cm}}\).
The determinant of the matrix \( M \) shown below is \(\underline{\hspace{2cm}}\). \[ M = \begin{bmatrix} 1 & 2 & 0 & 0 \\ 3 & 4 & 0 & 0 \\ 0 & 0 & 4 & 3 \\ 0 & 0 & 0 & 1 \end{bmatrix} \]
Given \( A = \begin{pmatrix} 2 & 5 \\ 0 & 3 \end{pmatrix} \), the value of the determinant \( |A^4 - 5A^3 + 6A^2 + 2I| \) is \(\underline{\hspace{2cm}}\).