Positive test cases and negative test cases

Question

what are positive test cases and negative test cases?

Upon googling about it i have found answers that are very confusing. Can anyone explain with

Answer 1

A positive test case tests that a system does what it is supposed to. Example: will allow you to login when valid credentials are supplied.

A negative test case tests that a system does not do things it shouldn't. Example: should not allow you to login when invalid credentials are supplied.