# Matrix multiplication 

Here are the matrices from the lab. They are written as lists of lists, 
which is a good way to write your answers too.

  a = [[1, 2, 3]] 
  B = [[6, 1],
       [1, 4]]
  C = [[1, 0, 0],
       [0, 1, 0],
       [0, 0, 1]]
  D = [[1, 1],
       [2, 2],
       [3, 3]]
  E = [[1, 2],
       [1, 2],
       [1, 2]]

## Exercises

Perform each of the following matrix multiplications if it is allowed.
If it's not allowed, explain why not.

1. BE
2. EB
3. BB
4. DD
5. CD
6. aC