I’m hearing “me-a-e” and not “me-ae”, where “ae” is a diphthong. I reported the audio as wrong.
Ugh, I translated as if the patellae were nominative and therefore the subject of placent, and as if tibi were dative with the verb. So, I didn't use the English idiom preferred by Duolingo, but ... "Do my dishes please you?" would seem to carry the sense of the Latin.
I tried it again, a week later--because it seems natural enough to me--but it's still not accepted.
You are right. That is what the Latin literally says. No “as if”. Patellae is nominative and the subject of placent, no matter how we translate it.
Singular and plural "you."
If "you" = one person, the forms of the pronoun are tū (nomin), tibi (dative), tē (accus) and tē (abl.); the possessive adjective ("your") is tuus, tua, tuum .
(Nomin = YOU, dative = TO / FOR YOU, accus. and abl. = YOU as object of preposition, etc.)
If "you" = more than one person, then vōs is the nominative/accusative form, and vōbīs is the dative/ablative form.
A plural "they" verb ends in -nt; a singular "he/she/it" verb ends in -t.
(So, placent is 3rd person plural; patellae "plates" is its subject. Patellae mihi placent , "The plates please me" = "I like the plates."
But placet is 3rd person singular; patella "a plate" could be its subject. Patella mihi placet , "The plate pleases me" = "I like the plate.")