Now the question is how do i use this NV_blend_equation_advanced when i don't want to use glew?
As with every extension:
0.) Read the extension's specification.
1.) Check whether the extension is available within the running GL context.
-- either the old way by using glGetString(GL_EXTENSIONS)
-- or the new way by using glGetStringi(...) if supported
2.) Because the extension seems to run without special routines, you probably don't need to resolve symbols against it.
3.) Call the appropriate functions with the appropriate parameters.
There is another source of information that is more understandable what all those new parameters mean. The slides have the one or other error as I've seen, but an understanding of what's going on can be fetched from the slides definitely.