Řešení je správné.

Roughly: RZHE-she-nee yeh SPRAAV-nay.

A few important details:

• Ř is a special Czech sound with no exact English equivalent. A good learner approximation is something between r and zh (the s in measure).
• š sounds like English sh.
• j in Czech sounds like English y, so je is pronounced yeh.
• é and í are long vowels.
• Czech stress is usually on the first syllable of the word:
  • ŘEšení
  • správné

So even though í and é are long, the stress still stays at the beginning.

Řešení is a noun, and in this sentence it means solution.

More specifically, it is a verbal noun related to the verb řešit, meaning to solve or to deal with. So řešení is literally something like solving / solution, depending on context.

In this sentence, it functions as the subject:

• Řešení = the solution
• je správné = is correct

Je is the 3rd person singular present tense of být (to be), so it means is.

So:

• Řešení = solution
• je = is
• správné = correct

Unlike in some languages, Czech normally does use the present tense of to be in sentences like this.

Because správné has to agree with řešení.

In Czech, adjectives agree with the noun in:

• gender
• number
• case

Řešení is neuter singular nominative, so the adjective must also be neuter singular nominative:

• masculine: správný
• feminine: správná
• neuter: správné

That is why the sentence is:

Řešení je správné.

It is neuter.

A lot of Czech nouns ending in -í are neuter, including many verbal nouns like:

• učení = learning
• čtení = reading
• psaní = writing
• řešení = solution / solving

Because řešení is neuter, the adjective becomes správné.

Here it is singular.

A learner might wonder because some Czech noun forms look the same in singular and plural. In fact, řešení can have the same form in both nominative singular and nominative plural.

What tells you it is singular here is the verb:

• je = is (singular)

If it were plural, you would expect:

• Řešení jsou správná. = The solutions are correct.

Not if you want a full sentence with the meaning The solution is correct.

• Řešení je správné. = full sentence
• správné řešení = correct solution (just a noun phrase, not a full sentence)

So if you remove je, you usually change the structure completely.

Yes, Czech word order is fairly flexible, but the neutral, most straightforward order here is:

Řešení je správné.

Other word orders are possible for emphasis or contrast, for example:

• Správné je řešení.
• Správné řešení to je.

These sound more marked or stylistic. For a basic neutral statement, Řešení je správné is the best choice.

No. Czech does not have articles like English a or the.

So řešení can mean:

• a solution
• the solution

Which one is intended depends on context.

In this sentence, English often translates it as The solution is correct or A solution is correct, depending on the situation.

Yes, very much.

In Řešení je správné, the diacritics are part of correct spelling and pronunciation:

• Ř is different from R
• š is different from s
• í and é show long vowels

So you should write:

• Řešení je správné.

not:

• Reseni je spravne.

People may still understand the version without diacritics in informal typing, but it is not proper standard spelling.