"Aqui estão respostas a perguntas frequentes."

Translation: Here are answers to frequently asked questions.

[sebastao]

Sometimes your damned for making sentences more natural in english. Therefore frquent questions should be accepted.

[AlexTheTutor]

"Frequently" is an adverb. These lessons are about adjectives. So, it should be "frequent questions". Reporting.. :p

[markmanson]

There is no "asked" in the example sentence

[soulzy]

True, but in english, the concept would still be "frequently asked questions" and hardly ever "frequent questions"