1000:z+6z-2z=410 решите подробно

                                                               1000/z+6z-2z=410                                                                1000/z+4z=410 Умножаем на z,                                 1000+ 4z^2=410z                                                                4z^2-410z+1000=0 Делим на 2,                                         2z^2-205z+500=0 Решаем квадратное ур. Находим  D=(-205)^2-4*2*500                                                                 D=42025-4000=38025. Находим два корня квадр. ур.   1)  z=(-(-205)+кв. корень из 38025)/2*2                                                                    z=(205+195)/4                                                                 z=400/4=100                                                           2)  z=(205-195)/4                                                                 z=2,5