Question

la media aritmética del doble de un entero y su cuadrado es 12 ¿Cuál es el entero?

Answer 1

Entero     = N
doble       = 2N
quadrado = N^2
media aritmética
                               (2N + N^2)/2 = 12
Resolviendo
                               N^2 + 2N = 24
                               N^2 + 2N - 24 = 0
Factorizando
                               (N + 6)(N - 4) = 0
Cada factor debe ser nulo
                               N + 6 = 0
                                                  N1 = - 6
                               N - 4 = 0
                                                  N2 = 4

                                                                     ENTERO
                                                                         - 6
                                                                       o
                                                                            4