2х + 5у - у в квадрате=6            2 х+у=11 пожалуйста решите функцию

     2х=11-у                                                                        yy-4y-5=0={                                                                                       y1+y2=4    11-y +5y-yy=6                                                               y1*y2=-5    2x=11-y                                                                          y1+y2=5-1={                                                                                         y1*y2=5*(-1)    yy-4y-5=0     x=(11-5)|2={         y=5     x=3                                x=6={                      или                    y=5                                y=-1