Question

If you multiply a matrix by the identity matrix, what is the result?

Answer 1

If you multiply a matrix `A` by an identity matrix `I` the result is `A`

Explanation:

The identity matrix is the only matrix, for which:

`A*I=I*A=A`.

This means that if you multiply any matrix `A` by identity matrix `I` the result is the matrix `A` (it does not matter if identity matrix is on the left or on the right )