It should be hablé since if it talking about someone else. If it were to be you, however, the sentence would be “Yo hablo con Juan.” Comprende?
Answer:
1) Voy a escribirsela
2) Voy a decirtela
3) Va a escribirla
4) Va a comprarlo
5) Va a explicarnos
Explanation:
Im fluent in spanish (bilingual) so I know how to do these :)
