M[4,3_1,2]-M[1,1_1,0]+M[1,1_1,4]

perform the indicated operations where possible

2 answers

What is the meaning of the 'underscore' _ ?

Are these matrices ?

Why, if they are different matrices, do they have the same name M ?

To add/subtract same-size matrices simply add/subtract the corresponding elements.
[4,3_1,2]-[1,1_1,0]+[1,1_1,4]

yes this is a matrice. when it through the m in there I thought it was right