Question

 If A =` [(1,-2 ,1),(2,1,3)]and B=[(2,1),(3,2),(1,1)]`

would it be possible to form the product matrix BA? If so, compute BA; if not give a reason
why it is not possible.

Answer 1

Product BA is possible

AB =` [(1,-2 ,1),(2,1,3)][(2,1),(3,2),(1,1)]`

       = `[(2,+2,-4,+1,2,+3),(3,+4,-6 ,+2 ,3,+6),(1,+2,-2,+1,1,+3)]`

       = `[(4,-3,5),(7,-4,9),(3,-1,4)]`