How can we identify the redundant constrain from the feasible base?

[mengtsinghua]

Hi,
I am a new learner about Simplex algorithem, just wonder how to identify the redundant constrain from the feasible base? e.g., from the attached screenshot, is there any solution or idea to identify the constrain of (x2 + x1 <= 4), please?

objection function: max(z) = x1 + 2x2
s.t. x1 - x2 <= -1 and x1 = 1 and x2 + x1 <= 4, x1 >=0 and x2 >=0.

Thanks for any kind of help.