Hello!As stated by pka it is correct. My question is why don't you get your hands a little dirty by proving it yourself. It really isn't that hard. Just write done two ARBITRARY nxm matrices and see if you get the results which you want. Please do this as it will help you and please show us your work.
Did your example have numbers and/or was a particular size? If yes, then what you showed might not be true in general. Why not show it in the general case? Try to do that and post back your work. If you need help with it then just ask.Hello!
Actually I did !
But I wasn't sure if my example is enough to represent the general case ( I thought that there might be some matrices under certain rules that might not apply for that rule)