Is sofware engineering is system engineering?

yes, it very important

Mechanical engineering is the design of everything from cars designed to be used in systems engineering.

software engineering is the process of of developing a application(software) it ia considered only with the lifecycle of development of the application. which can be dine using any computer...

A software engineer works on software, while a system engineer will just work on the system. They are different because the system could be the BIOS, operating system, hard drive, memory, and other...