Answer:
Possessive adjectives indicate which person possesses, or owns, a given noun, but must match the thing being possessed in gender (when applicable) and number. There are three ways to express possession in Spanish, two ways using adjectives and one way without adjectives.
Possessive Adjectives
There are two forms of possessive adjectives in Spanish: the short form and the long form. Each has its own form and uses.
1. Short-form Possessive Adjectives
Short-form possessive adjectives are the most common possessive adjectives and must agree with the noun in gender and number for 1st and 2nd person plural, and only in number for all other forms. They are placed before the noun they modify.
Short-form Possessives
Singular Plural
1st person mi(s) (my) nuestro, nuestra (our) nuestros, nuestras
2nd person tu(s) (your familiar) vuestro, vuestra (your familiar) vuestros, vuestras
3rd person su(s) (his, her, your formal) su(s) (their, your formal)
No More Definite Articles
Notice that the definite articles el, la, los, and las are omitted when the possessive adjective precedes the noun.
Mi amigo peruano es guapo. (My Peruvian friend is handsome.)
¿Dónde están tus zapatos? (Where are your shoes?)
Nuestra casa es muy grande. (Our house is very big.)
Vuestras reservaciones son a las ocho. (Your reservations are at 8:00.)
Don't Use When...
Possessive adjectives are not used when possession is obvious (bodyparts, clothing).
Me duele el brazo. (My arms hurts.)
Me lavo el cabello. (I wash my hair.)
2. Long-form Possessive Adjectives
Long-form possessive adjectives are used less often than the short-form possessive adjectives as they are used to emphasize the owner of one noun or to contrast one owner with another. They are placed after the noun they modify. All long-form possessive adjectives must agree with the noun they modify in gender and number.
Long-form Possessives
Singular Plural
1st person mío, mía (mine) míos, mías nuestro, nuestra (ours) nuestros, nuestras
2nd person tuyo, tuya (yours familiar) tuyos, tuyas vuestro, vuestra (yours familiar) vuestros, vuestras
3rd person suyo, suya (his, hers, yours formal) suyos, suyas suyo, suya (theirs, yours formal) suyos, suyas
Determine, Then Possess
Notice that the definite articles el, la, los, and las are used to determine the noun while the long-form possessive adjective comes later.
¿Dónde están los zapatos tuyos? (Where are your shoes?)
Las reservaciones vuestras son a las ocho. (Your reservations are at 8:00.)
Esta es mi silla y aquel es la silla tuya. (This is my chair and that one is yours.)
Possession without adjectives
Possession can be expressed a third way without the use of possessive adjectives by using the following formula:
Possession Formulation
un + de + pronoun/name of owner
Atlanta es la capital de Georgia. (Atlanta is the capital of Georgia. OR Georgia´s capital is Atlanta.)
Es la silla de él. (It´s his seat.)
La casa de Elena está allí. (The house of Elena is there. OR Elena´s house is there.)
La pizzería de Alán (The pizzeria of Alán OR Alán´s pizzeria.)
Don't Use For...
This formula cannot be used with yo or tú.