If $A=\begin{bmatrix}1 & 2\\2 & 1\end{bmatrix}$ and $f(x)=x^2-2x-3$, then $f(A)$ is equal to

The value of $\begin{vmatrix} x & x+1 \\ x-1 & x \end{vmatrix}$ is:

If P and Q are symmetric matrices, then QP-PQ is

If $P = \begin{bmatrix}0 & 1\\ 1 & 1\end{bmatrix}$ and $Q = \begin{bmatrix}0 & -1\\ 1 & 0\end{bmatrix}$, then which of the following are correct?

(A) $P+Q$ is a singular matrix.

(B) $P-Q$ is a symmetric matrix.

(C) $P$ and $Q$ are non-singular matrices.

(D) $(P+Q)(P-Q) \neq P^2 - Q^2$

Choose the correct answer from the options given below:

If $\begin{vmatrix}x-2 & 2x-3 & 3x-4\\x-4 & 2x-9 & 3x-16\\x-8 & 2x-27 & 3x-64\end{vmatrix} = 0$ then the value of x is:

Let $I = \begin{bmatrix}1 & 0\\0 & 1\end{bmatrix}$ and $A = \begin{bmatrix}1 & -2\\2 & 4\end{bmatrix}$ be two matrices such that $8A^{-1} = kI - A, k \in \mathbb{R}$, then the value of $k$ is:

If $\begin{vmatrix} 1+a & 1 & 1 \\ 1 & 1+b & 1 \\ 1 & 1 & 1+c \end{vmatrix}$, where a, b and c are non zero constants, then the value of $\frac{1}{a} + \frac{1}{b} + \frac{1}{c}$ is