find the sum.\n$\\begin{bmatrix}-1&7\\\\-9&21\\\\2&14\\end{bmatrix}+\\begin{bmatrix}12&-12\\\\-2&3\\\\12&18\\…

Explanation:

Step1: Add the first - row first - column elements

For matrix addition, we add the corresponding elements. The first - row first - column element of the first matrix is (-1) and of the second matrix is (12). So, (-1 + 12). [ -1+12=11 ]

Step2: Add the first - row second - column elements

The first - row second - column element of the first matrix is (7) and of the second matrix is (-12). So, (7+( - 12)). [ 7+( - 12)=7 - 12=-5 ]

Step3: Add the second - row first - column elements

The second - row first - column element of the first matrix is (-9) and of the second matrix is (-2). So, (-9+( - 2)). [ -9+( - 2)=-9 - 2=-11 ]

Step4: Add the second - row second - column elements

The second - row second - column element of the first matrix is (21) and of the second matrix is (3). So, (21 + 3). [ 21+3=24 ]

Step5: Add the third - row first - column elements

The third - row first - column element of the first matrix is (2) and of the second matrix is (12). So, (2+12). [ 2 + 12=14 ]

Step6: Add the third - row second - column elements

The third - row second - column element of the first matrix is (14) and of the second matrix is (18). So, (14+18). [ 14 + 18=32 ]

Answer:

(\begin{bmatrix}11&-5\-11&24\14&32\end{bmatrix})