Answer:
1. Mi tía es mexicana. Vive en Guadalajara.
<em>My aunt is Mexican. She lives in Guadalajara.</em>
2. Mi primo no es rubio, es moreno.
<em>My cousin is not blond, he is brown.</em>
3. Mi novio cree que la clase no es fácil; es difícil.
<em>My boyfriend thinks that the class isn't easy, it is hard.</em>
4. Los libros son interesantes; me gustan mucho.
<em>Books are interesting; I like them a lot.</em>
5. Mis hermanos son antipáticos; no tienen muchos amigos.
<em>My brothers are unfriendly, they do not have many friends.</em>
Explanation:
All of these sentences are in <u>Present Simple</u> tense.
For the sentences to be correct you have to take into account the gender and number of each noun, so it agrees with the adjective - otherwise it will not make sense and be incorrect. For example, <em>mexican</em><u><em>a</em></u> refers to a Mexican woman, while <em>mexican</em><u><em>o</em></u> refers to a Mexican man.