Answer:
1. Mi tía es mexicana. Vive en Guadalajara.
My aunt is Mexican. She lives in Guadalajara.
2. Mi primo no es rubio, es moreno.
My cousin is not blond, he is brown.
3. Mi novio cree que la clase no es fácil; es difícil.
My boyfriend thinks that the class isn't easy, it is hard.
4. Los libros son interesantes; me gustan mucho.
Books are interesting; I like them a lot.
5. Mis hermanos son antipáticos; no tienen muchos amigos.
My brothers are unfriendly, they do not have many friends.
Step-by-step explanation:
All of these sentences are in Present Simple 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, mexicana refers to a Mexican woman, while mexicano refers to a Mexican man.