Can you add a picture of your notes please.
Tú casa es grande.

The difference between "tú" and "usted" depends on the formality. "Tú" is used <u>when talking to friends or relatives (informal)</u> while "usted" is used <u>when talking to older people or a person of high social rank (formal)</u>.
In this case we want to write the <u>informal</u> form of "tú", so we use "tú". Also, when dealing with <u>permanent states</u>, the verb "ser" (to be) is used.
Question 1: Sr. Rodriguez *tiene* sesenta años
Question 2: Ella *es* inteligente y bonita
Question 3: Los estudiantes *van* a la escuela
Question 4: Yo *tengo* tres clases hoy
Question 5: Nosotros *vamos* a comer en el restaurante