Do I deserve full credit for this very simple proof?

[Helicobacter]

Please take a look and let me know if it is good.

My professor took off 75% from my last proof and just simply put a line through it. So, now I bought Intro to Analysis by Maxwell to practice proofs. The first proof in the book is what I've tried in the attachment. I don't want to memorize Maxwell's proof but do my own, but at the same time I want to know if I'm doing things the right way.

[g_edgar]

Only the professor can tell you what was desired for this. Not us.

[Helicobacter]

This was not the proof where 75% were removed.

This is a practice proof from the text. I want to know whether my way of doing it is satisfactory as well.

[Werg22]

Yes, it's correct.