Adjectival Nouns

Question 1

同じ

onaji

Answer 1

彼と父親の趣味は同じだ
He and his father’s hobby are the same.

but it also can be used as adjective (形容詞) with an irregularity that the -i ending is dropped. For example,

彼は父親と同じ趣味をもっている。 He has the same hobby with his father

But 同じく has special usage that mean そして同じように, for example.

A-さん：　私は～部所属の～と申します。　(I am from ~ department and my name is ~)

B-さん：　同じく～部所属の～と言います。 (I am also from ~ department and I am … )