Is the word negativo the same in Brazilian and European Portuguese?

Yes.

The spelling, meaning, and grammatical function of "negativo" are identical in both Brazilian and Continental Portuguese. The only difference is pronunciation. In Brazilian Portuguese, the vowels are generally more open and the syllables are more clearly articulated. In Continental Portuguese, unstenuated vowels undergo significant reduction; for example, the "e" is often pronounced as a very short, muffled "i," making the word sound more clipped and less rhythmic than in Brazil.

Brazilian Portuguese

1. O resultado do exame deu negativo. (The test result was negative.)
2. O ônibus teve um impacto negativo na viagem. (The bus had a negative impact on the trip.)
3. Ele é muito negativo sobre o futuro. (He is very negative about the future.)
4. O saldo da conta ficou negativo. (The account balance became negative.)
5. A resposta do professor foi negativa. (The teacher's answer was negative.)

Continental Portuguese

1. O resultado do exame deu negativo. (The test result was negative.)
2. O autocarro teve um impacto negativo na viagem. (The bus had a negative impact on the trip.)
3. Ele é muito negativo sobre o futuro. (He is very negative about the future.)
4. O saldo da conta ficou negativo. (The account balance became negative.)
5. A resposta do professor foi negativa. (The teacher's answer was negative.)