Answer
The expression "$A^2$" is undefined.
Work Step by Step
1. Check if the expression is defined.
$A^2$ is the same as $AA$, which is a multiplication.
For a matrix multiplication, the length of the row in the first matrix must be equal to the length of the column in the second one.
Length of the row in A: 3
Length of the column in A: 2
Therefore, this expression is undefined.