If the nouns are of different genders, the adjective is pl. masc., as—
El encaje y las guarniciones han salido caros: The lace and trimmings came out dear.
EXCEPTION—
When all the several nouns preceding the adjective are in the plural, and all referring to things (not persons), the adjective may be made to agree in gender with the noun last mentioned, as—
Los tornillos y las tuercas están bien ajustados (or ajustadas): The screws and nuts are well adjusted. It is better to avoid this construction
(1) By saying "las tuercas y los tornillos están bien ajustados."
(2) By using an adjective having the same termination for masculine and feminine.
(3) By giving a different turn to the sentence, as: "Son de buen ajuste".
Adjectives that qualify the fem. nada (nothing) are always used in the masculine—
Nada bueno espero de él: I expect nothing good from him.