I've been taught that у and к both translate to "at" (as in
chez in French).
"У меня есть книга" = "At me, there's a book" = "I have a book"
"Я к врачу иду." = "I go at the doctor"/"Je vais chez le docteur" = "I'm going to the doctor."
But then, how do we choose? I came across this sentence:
"Я не хочу жить у вас"
and I wondered why we could not say "к вам" instead.
Are there specific rules for у/к?