What is the sum of the matrices (12)\begin{pmatrix} 1 & 2 \end{pmatrix}(12) and (34)\begin{pmatrix} 3 & 4 \end{pmatrix}(34)?
(46)\begin{pmatrix} 4 & 6 \end{pmatrix}(46)
(38)\begin{pmatrix} 3 & 8 \end{pmatrix}(38)
(12)\begin{pmatrix} 12 \end{pmatrix}(12)
Not defined