Final answer:
To write sentences in the negative form in Spanish, use the word 'no' before the verb and after the subject.
Step-by-step explanation:
To write the sentence 'El cielo es morado' in the negative, we use the word 'no' before the verb 'es' and after the subject 'cielo'. So, the negative form is 'El cielo no es morado'.
Similarly, to write the sentence 'Los carros son nuevos' in the negative, we use the word 'no' before the verb 'son' and after the subject 'carros'. So, the negative form is 'Los carros no son nuevos'.
Learn more about negative sentences in Spanish