A = \(\begin{bmatrix}1&2\\3&4\end{bmatrix}\)
A2 = \(\begin{bmatrix}1&2\\3&4\end{bmatrix}\) \(\begin{bmatrix}1&2\\3&4\end{bmatrix}\) = \(\begin{bmatrix}7&10\\15&22\end{bmatrix}\)
∴ f(A) = 2A2 - 3A + 5I
= 2\(\begin{bmatrix}7&10\\15&22\end{bmatrix}\) - 3\(\begin{bmatrix}1&2\\3&4\end{bmatrix}\) + 5\(\begin{bmatrix}1&0\\0&1\end{bmatrix}\)
= \(\begin{bmatrix}16&14\\21&37\end{bmatrix}\)