Can you multiply Matrices?

To determine whether or not matrices can be multiplied you first have to write a dimensions statement.

Example of a dimensions statement:
[ 5  7 ]  [ 9 ]
[ 3  4 ]  [ 8 ]

Dimensions statement:
2 X 2 times 2 X 1

These matrices can be multiplied, so you would multiply row X column.
Then you get the sum of the products.
The numbers in yellow tell you that you can multiply the matracies.
The numbers in green tell you the size of the final matrix.