Answer:
Comen | Habla | Comparten | o, es, e, imos, is, en
Step-by-step explanation:
2. "Mis amigos comen la pizza" - it's comen because you are not talking about yourself AND your friends eating in this case, therefore it's the ellos conjugation (-en) for -er verbs.
3. "Ella no habla mucho en clase." - it's "habla" in this case because it's the 3rd person (él/ella), with it being "her" in this case. I believe "hable" is the subjunctive form, and would (from my understanding) be used to express a wish for the person to speak in class. I believe since this is just stating a fact that "she doesn't speak much in class", that it should be "habla". "hablas" is the "you" (tú) conjugation of hablar.
4. "Javier y Jan comparten la comida" - It's "comparten" because the they/them (ellos/ellas) conjugation of compartir is "comparten". Javier y Jan are two people not including you, so it would be "them".
5. The "IR" verb endings in Spanish are... "o, es, e, imos, is, en". It's been a while since I've touched up on my IR/ER endings, but to my understanding they are more or less the same in the present-tense with the exception of nosotros and vosotros being "emos/imos" and "éis/ís" respectively.
Hopefully this helped.