# 5.5E: Zeros de funções polinomiais (exercícios)

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Para os exercícios a seguir, use o Teorema do Zero Racional para ajudá-lo a resolver a equação polinomial.

25. $$2 x^{3}-3 x^{2}-18 x-8=0$$

26. $$3 x^{3}+11 x^{2}+8 x-4=0$$

27. $$2 x^{4}-17 x^{3}+46 x^{2}-43 x+12=0$$

28. $$4 x^{4}+8 x^{3}+19 x^{2}+32 x+12=0$$

Para os exercícios a seguir, use a Regra de Sinais de Descartes para encontrar o número possível de soluções positivas e negativas.

29. $$x^{3}-3 x^{2}-2 x+4=0$$

30. $$2 x^{4}-x^{3}+4 x^{2}-5 x+1=0$$