La memoria económica explica el presupuesto desglosado.

Because la memoria económica is being treated as a specific thing, not just any financial report in general. Spanish uses definite articles very often where English might also use the.

Here, la goes with memoria, which is a feminine singular noun.

Because económica is an adjective describing memoria, and adjectives usually agree in gender and number with the noun they describe.

• memoria = feminine singular
• so the adjective must also be feminine singular: económica

Compare:

• la memoria económica
• el informe económico

Same idea, different noun gender.

Not really. In formal Spanish, especially in Spain, memoria can mean a report, written account, or supporting document, not just memory in the everyday mental sense.

So memoria económica is a fixed administrative/formal expression. It usually refers to a document explaining the financial side of a project, proposal, activity, or budget.

Explica is the:

• third person singular
• present indicative
• of the verb explicar

So it means he/she/it explains.

In this sentence, the subject is la memoria económica, so explica means it explains.

Because Spanish normally leaves out subject pronouns when they are not needed.

The verb form explica already tells you it is he/she/it in the present tense, and the noun la memoria económica is right there as the subject, so adding ella would usually be unnecessary.

Spanish often sounds more natural without the pronoun:

• La memoria económica explica...
  not usually
• Ella explica...

Because presupuesto is the direct object of explica, and direct objects usually do not take a unless they refer to a specific person or sometimes a personified being.

So:

• explica el presupuesto = correct
• explica al presupuesto = not correct here

You use the personal a mainly with people:

• Explica el problema a Juan = She explains the problem to Juan.

There, a Juan is the indirect object, not the direct object.

Yes, but in formal written Spanish, especially in administrative or academic contexts, explicar can sound a bit broader than everyday English explain.

Here it can mean something like:

• explains
• sets out
• details
• accounts for

So the sentence suggests that the financial report lays out or clarifies the itemized budget.

Because in Spanish, descriptive adjectives are very often placed after the noun.

So:

• el presupuesto desglosado = the itemized / broken-down budget

That is the normal order.

Putting the adjective before the noun is usually not natural here. Desglosado presupuesto would sound very unusual.

Because desglosado describes presupuesto, and presupuesto is masculine singular.

So the adjective must match:

• el presupuesto desglosado
• la memoria económica

Each adjective agrees with its own noun.

In this sentence, it is functioning as an adjective.

It comes from the verb desglosar, which means to break down, to itemize, or to separate into parts. The form desglosado is a past participle, but here it is being used adjectivally:

• un presupuesto desglosado = an itemized budget

This is very common in Spanish: past participles are often used like adjectives.

Yes, but this version is the most straightforward and natural.

Spanish word order is more flexible than English, but the basic structure here is very standard:

• subject: La memoria económica
• verb: explica
• object: el presupuesto desglosado

You could change the order for emphasis, but in neutral written Spanish this version is clear and natural.

No. Although económico / económica can sometimes mean cheap or inexpensive, that is not the meaning here.

In memoria económica, it means economic, financial, or budget-related.

Context is what tells you which meaning is intended. In an administrative phrase like this, the financial meaning is the natural one.