Answer:
5. enciende
6. pienso
Explanation:
Regardless of the fact that these verbs are considered irregulars, to choose the correct conjugated form take a look at the pronoun being used.
Since each pronoun as is own dedicated ending (which is why in Spanish you can omit the pronouns in sentences), focus on it to select the proper conjugation.
El Senor Leon = el (he) ~-a / -e => enciende
Yo (I) ~ -o => pienso
