"Large and tasty coffee"
Translation:Duża i smaczna kawa
The form of every adjective depends on the gender of a noun:
If a noun is feminine then you should use dużA : duża kawa, duża miska
If a noun is masculine use dużY : duży dom, duży stół
If a noun is neuter use dużE : duże zwierzę, duże okno
For plural there are two forms:
duzi for groups of people if there's at least one man there: duzi chłopacy, duzi ludzie
duże for all the other nouns: duże okna, duże miski, duże kobiety
Duolingo shows the gender of a noun next to the translation. But if you are still not sure how the form you need sounds like, you can check at Wiki: https://pl.wiktionary.org/
The adjectives don't match the noun grammatically in your answer. Your adjectives are in Nominative, but "kawę" is Accusative. It should be "Duża i smaczna kawa", in Nominative (because this is just a phrase outside of a sentence, so it should take Nominative, which is the basic case).
If it was a sentence like "I am drinking a large and tasty coffee", that would be "Piję dużą i smaczną kawę", with "large and tasty coffee" being a direct object and thus taking Accusative.