For adding matrices, their dimension should be equal.
\First write the dimension of the matrix.
\The first matrix is 
The matrix has 2 rows and 1 column, so dimensions of matrix are
..
The second matrix is 
The matrix has 2 rows and 1 column, so dimensions of matrix are
.
The third matrix is 
The matrix has 2 rows and 1 column, so dimensions of matrix are
.
The dimensions of matrix are equal. The operation of addition is possible.
\Add and Subtract corresponding elements
\
Add and Subtract corresponding elements
\
(Simplify)
The solution is
.