We want to subtract the second matrix from the first matrix. The steps are shown below
![\begin{gathered} D\text{ = }\begin{bmatrix}{3} & {1} & {0} \\ {-\text{ 1}} & {2} & {4} \\ {9} & {7} & {-\text{ 2}}\end{bmatrix}-\text{ }\begin{bmatrix}{5} & {2} & {-\text{ 4}} \\ {1} & {12} & {3} \\ {11} & {3} & {-\text{ 2}}\end{bmatrix}=\text{ }\begin{bmatrix}{3\text{ - 5}} & {1\text{ - 2}} & {0\text{ - - 4}} \\ {-\text{ 1 - 1}} & {2\text{ - 12}} & {4\text{ - 3}} \\ {9\text{ - 11}} & {7\text{ - 3}} & {-\text{ 2 - - 2}}\end{bmatrix} \\ D\text{ = }\begin{bmatrix}{-\text{ 2}} & {-\text{ 1}} & {0\text{ + 4}} \\ {-\text{ 2}} & {-\text{ 10}} & {1} \\ {-\text{ 2}} & {4} & {-\text{ 2 + 2}}\end{bmatrix} \\ D\text{ = }\begin{bmatrix}{-\text{ 2}} & {-\text{ 1}} & {4} \\ {-\text{ 2}} & {-\text{ 10}} & {1} \\ {-\text{ 2}} & {4} & {0}\end{bmatrix} \end{gathered}]()
The rows are horizontal while the columns are vertical
d11(Term in row1 and column 1) = - 2
d12(Term in row1 and column 2) = - 1
d13(Term in row1 and column 3) = 4
d21(Term in row2 and column 1) = - 2
d22(Term in row2 and column 2) = - 10
d31(Term in row 3 and column 1) = - 2