French language Q&A Forum

I found this sentence interesting:

Nous n'avons acheté aucune voiture.

Don't both parts of a negation (ne + plus/jamais/que/etc) usually go before the participle?

I'm reading an example using merci de with an action already done. It says to use Merci de + [Infinitif Passé] and gives the following example:

C'était très difficile, merci de m'avoir aidée.

Please, can you explain why aidée is feminine?

Bonjour Madame,

I asked this doubt a day ago but was unable to understand the reason behind it. The link is -

https://progress.lawlessfrench.com/questions/view/a-small-french-correction

Please provide further illumination.

Bonne journée !