Adjectives

Question 1

Na-adjective

Answer 1

The same conjugation rules as a noun, but can also directly modify a noun by placing な in between the adjective and the noun
More details see Obenkyo 3.3 Adjectives

Question 2

Na-adj example - ‘Quiet person’

Answer 2

静かな人

Question 3

i-adjective

Answer 3

An adjective that always ends in い. How to distinguish between i-adjectives and na-adjectives that end in い is that most na-adjectives of that type are written in Kanji, apart from a couple of exceptions
Doesn’t need a な in between adjective and noun
Never attach だ to the end of i-adjectives

Question 4

i-adjective conjugation rules

Answer 4

Negative - Replace い with くない
Past - Replace い with かった
Negative Past - Replace い with くなかった