All matrices can be factorised, usually in a variety of ways.

所有矩阵通常都能以各种方式因式分解。

However, Laplace expansion is efficient for small matrices only.

但是，拉普拉斯展开仅对小型矩阵有效。

It means they are the inverse matrices.

这就意味着它们是互逆的两个矩阵。

OK, now we know how to multiply matrices.

好，现在我们知道怎么把两个矩阵相乘了。

So, what does it mean to multiply matrices?

那么，两个矩阵乘起来是什么意思？