Eu discordo do resultado da prova.

Yes. In Brazilian Portuguese, subject pronouns are often optional because the verb ending already shows who the subject is.

• (Eu) discordo = I disagree
• The -o ending in discordo tells you it is I

You include eu when you want to:

• add emphasis
• create contrast
• avoid ambiguity

So both are correct:

• Eu discordo do resultado da prova.
• Discordo do resultado da prova.

The second one is very natural in everyday Portuguese.

Because discordar normally uses the preposition de.

So in Portuguese, the pattern is:

• discordar de algo = to disagree with something
• discordar de alguém = to disagree with someone

Examples:

• Discordo de você. = I disagree with you.
• Discordamos da decisão. = We disagree with the decision.

This is different from English, where you simply say disagree with. In Portuguese, you need to remember that discordar goes with de.

Because Portuguese commonly contracts the preposition de with definite articles.

Here:

• de + o = do

So:

• do resultado = de o resultado

This contraction is required in normal Portuguese.

Common de contractions:

• de + o = do
• de + a = da
• de + os = dos
• de + as = das

Examples:

• do livro
• da prova
• dos alunos
• das respostas

Because prova is a feminine noun, so it takes the feminine article a.

• de + a = da

So:

• da prova = of the test/exam

In the full phrase:

• o resultado da prova literally means the result of the test

It depends on context.

Resultado can mean:

• result
• outcome
• sometimes the published result of an exam or selection process

In school/test contexts, resultado da prova could mean:

• the result of the test
• the outcome
• possibly the scoring/result that was given

If you specifically want grade, Portuguese often uses:

• nota = grade/score

So:

• Discordo da nota da prova. = I disagree with the test grade.
• Discordo do resultado da prova. may sound a bit broader than just the number/grade.

Portuguese uses definite articles more often than English.

Here:

• o resultado = the result
• a prova = the test

Portuguese frequently uses articles with nouns where English may or may not use them, especially when referring to something specific.

So do resultado da prova sounds natural because it refers to:

• a specific result
• of a specific test

Leaving out the articles here would usually sound unnatural:

• discordo de resultado de prova is not the normal way to say this

They overlap, but they are not always identical.

In Brazilian Portuguese:

• prova often means an important test, exam, or assessment, especially in school
• teste can mean a test too, but often sounds more general, informal, or like a check/trial

Examples:

• Tenho prova amanhã. = I have an exam/test tomorrow.
• Vamos fazer um teste. = Let’s do a test/tryout/check.

In many school contexts, prova is the more natural word.

A rough pronunciation guide in Brazilian Portuguese is:

• eu ≈ eh-ooh / yoh
• discordo ≈ jees-KOR-doo or dees-KOR-doo, depending on accent
• do ≈ doo
• resultado ≈ heh-zool-TAH-doo
• da ≈ dah
• prova ≈ PROH-vah

A few useful notes:

• The r in resultado is usually pronounced like an English h at the beginning of the syllable in many Brazilian accents.
• The d before o often sounds like a normal d.
• Unstressed final o often sounds like oo in Brazilian Portuguese.

The main stress falls on:

• disCORdo
• resulTAdo
• PROva

Yes.

You can say:

• Discordo de você. = I disagree with you.
• Discordo do professor. = I disagree with the teacher.
• Discordo da minha mãe. = I disagree with my mother.

You can also disagree with ideas, decisions, results, opinions, and so on:

• Discordo da opinião dele.
• Discordo da decisão.
• Discordo do resultado.

Both are correct, but they are not always used in exactly the same way.

• discordar de = to disagree with
• não concordar com = to not agree with

Examples:

• Discordo do resultado da prova.
• Não concordo com o resultado da prova.

In many situations, não concordo com can sound a little softer or less direct than discordo, though this depends on tone and context.

Also note the different prepositions:

• discordar de
• concordar com

Discordo is the 1st person singular, present indicative form of discordar.

Conjugation in the present:

• eu discordo = I disagree
• você discorda = you disagree
• ele/ela discorda = he/she disagrees
• nós discordamos = we disagree
• vocês discordam = you all disagree
• eles/elas discordam = they disagree

So in this sentence, discordo specifically means I disagree.

It can, depending on tone and context.

Eu discordo do resultado da prova is direct and clear. It is not rude by itself, but it can sound firm, especially if you are challenging a grade, a correction, or an official result.

If you want to sound softer, you could say:

• Acho que houve um engano no resultado da prova. = I think there was a mistake in the test result.
• Não concordo com o resultado da prova.
• Gostaria de revisar o resultado da prova. = I would like to review the test result.

So the original sentence is perfectly correct, but tone matters.