решите уравнение(х^2-9x)(x^2-9x-12)=160

x²-9x=tt(t-12)=160t²-12t-160=0D=12²+4*160=28²t_1=(12+28)/2=20                  t_2=(12-28)/2=-8  x²-9x=20                                  x²-9x=-8   x²-9x-20=0                                x²-9x+8=0     D=81+80=161                           D=81-32=49x_1=(9+√161)/2                               x_3=(9+7)/2=8  x_2=(9-√161)/2                               x_4=(9-7)/2=1