My professor told me to look on YouTube, lol.

I understand how to do equally sized matrices and to do something like A3x3 * B3x1 but how would you do A3x3 * B3x2?

What I mean is:

For 3x3 * 3x1 you use the same (only) column in B for each row of A.

For 3x3 * 3x3 each row of A matches a column in B.

What would you do for 3x3 * 3x2? Use column 1 or 2 of B for the third row of A or something odd with the second row of A?

Thanks in advance for any response.