$\"\"$

For subtracting matrices, their dimension should be equal.

First write the dimension of the matrix.

The dimensions of matrix C and D are $\"\"$ .

The operation C + 1/3D is possible.

$\"\"$

Multiply the matrix D by 1/3.

$\"\"$

$\"\"$ (Divide each element by 1/3)

$\"\"$ (Simplify)

$\"\"$

Multiply the matrix C + 1/3D.

$\"\"$

$\"\"$ (Multiply each element by 2)

$\"\"$ (Simplify)

$\"\"$

C + 1/3D $\"\"$ .