yo -o nosotros/nosotras -amos/-emos/-imos
tu -as/-es vosotros/vosotras -ais/-eis/is
el/ella/ud -a/e ellos/ellas/uds -an/en
The ending depends on the end of the verb. For example, The verb hablar (to talk) ends in -ar. So, to conjugate it, it would look like this:
yo hablo nosotros/nosotras hablamos
tu hablas vosotros/vosotras hablais
el/ella/ud habla ellos/ellas/uds hablan
-er and -ir verbs share some of the endings. If there is no ending including the letter i in the chart above, then use the -er ending.
To know what form to conjugate, look for the word not in bold in the chart above.
Answer:
1. estan.
2. apagan. (los estudiantes is similar to ellos because it refers to them)
3. sabe (Jorge is similar to el because it refers to he)
4. tiene. (la casa is like ella. Add an i to tener because it's a 'special' verb. Basically, in yo,tu,el,ellos forms, there's an i in front of the first e)
5. pone. (alejrando is like el)
6. hago. (there's a g because hacer is a go-in-the-yo verb, meaning when conjugating to yo form, there should be the word go in the verb)
7. ofrece
8. saca
9. decimos
i hope this helps