The core of linear algebra or linear equation

Of course, equations will be encountered everywhere.

Determinant matrix vector is a tool to solve equations.

Of course, they also derive some other applications.

There are many calculations in the postgraduate entrance examination.

Just because you calculate more and prove less doesn't mean you don't understand.

Algebra is abstract, but it is not difficult to understand its essence.

Read more textbooks, read them again and again, fully understand them, see some problem-solving methods, and then practice by yourself.