Question

Resolva, em R as inequações a seguir:
A) X* - 9x +20 > 0 B) -x* + 16 》0
C) X* - 6x+ 9《0
D) -X* - 1< 0
Pvfr me ajudem?

Answer 1

  Vou ajudar com duas

        A)
                  x^2 - 9x + 20 > 0
             fatorando
                  (x - 4)(x - 5 ) > 0
                     x - 4 > 0
                                       x1 > 4
                     x - 5 > 0
                                       x2 > 5
                                                      Solução (x1)inter(x2): x > 4
                                                          veja na reta numérica
  
                                  _____0___________|________|___________
                                                                   4               5
                                                                    |--------------------------->
                                                                             x > 4

        D)
                   - x^2 - 1 < 0
           multiplicando por (- 1)  [inverte sentido da igualdade]
                     x^2 + 1 > 0
                          x^2 = - 1
                              x = √(- 1)     SEM SOLUÇÃO EM R