Question

1- Encontre os zeros de cada uma das funçoes abaixo =(4=0)
A)F(x)= -x² +8x-15
B) m (x)=-10x²
c)q(x)= -x²/2+x

Answer 1

Para determinar os zeros a função deve ser nula

A)
                - x^2 + 8x - 15 = 0
               -(x^2 - 8x + 15) = 0
      Fatorando
                 - (x - 5)(x - 3) = 0
                         x - 5 = 0
                                         x1 = 5
                        x - 3 = 0
                                         x2 = 3           S = { 3, 5 }
B)
                  - 10x^2 = 0
                        x^2 = 0/-10
                               = 0
                                                 x1 = x2 = 0
                                                                         S = { 0 }
C)
                   - x^2/2 + x = 0
          multiplicando todo por 2
                   - x^2 + 2x = 0
          fatorando
                   - x(x - 2) = 0
                             - x = 0
                                             x1 = 0
                       x - 2 = 0
                                             x2 = 2          S = { 0, 2 }