##### Exercise7

Suppose that $$A$$ and $$B$$ are $$n\times n$$ matrices.

1. If $$A$$ and $$B$$ are both invertible, use determinants to explain why $$AB$$ is invertible.

2. If $$AB$$ is invertible, use determinants to explain why both $$A$$ and $$B$$ is invertible.

in-context