Which of the following statements is incorrect regarding matrices ?

For any matrices A and B of suitable orders,

If A and B are symmetric matrices of the same order, then which one of the following is true?

Let A be the matrix $\begin{bmatrix} 3 & -4 \\ 1 & -1 \end{bmatrix}$. If A is expressed as the sum of P and Q, where P is a symmetric and Q is a skew symmetric matrix, then which of the following options define P and Q correctly?

If $\begin{bmatrix} x+2y & -y \\ 3x & 4 \end{bmatrix} = \begin{bmatrix} -4 & 3 \\ 6 & 4 \end{bmatrix}$, then $3x+2y$ is equal to

If $A = \begin{bmatrix} 1 & -2 & 3 \\ -4 & 2 & 4 \end{bmatrix}$ and $B = \begin{bmatrix} 1 & -2 \\ 3 & -4 \\ 2 & 4 \end{bmatrix}$, then $AB$ is :

If A is a square matrix of order 3 such that $A( {adj } A) = \begin{bmatrix} -2 & 0 & 0 \\ 0 & -2 & 0 \\ 0 & 0 & -2 \end{bmatrix}$, then $|A|$ is equal to

Let A be a non-singular matrix of order 3 and $|A| = 15$, then $|adj A|$ is equal to