$\"\"$

The matrices are $\"\"$ , $\"\"$ , $\"\"$ and $\"\"$ .

Find $\"\"$ .

$\"\"$ (Original expression)

$\"\"$ (Substitute $\"\"$ and $\"\"$ )

$\"\"$ (Multiply by a scalar: $\"\"$ )

$\"\"$ (Add: $\"\"$ )

$\"\"$ (Product of two same signs is positive)

$\"\"$ (Simplify) $\"\"$

The value of $\"\"$ is $\"\"$ .