x² - 10x + 21 = 0
                        ( 3 )

x² + 16x + 64 = 0
                        (    )

x² + 10x + 24 = 0
                        (    )

x² - 10x + 25 = 0
                        (    )

x² + 7x + 12 = 0
                        (    )

x² + 8x + 16 = 0
                        (    )

x² - 7x + 12 = 0
                        (    )

x² + 13x + 36 = 0
                        (    )

x² - 7x + 12 = 0
                        (    )

x² - 11x + 24 = 0
                        (    )

                      +[    ]

x² + 11x + 30 = 0
                        (    )

x² - 9x + 20 = 0
                        (    )

x² + 15x + 54 = 0
                        (    )

x² + 10x + 25 = 0
                        (    )

x² - 17x + 72 = 0
                        (    )

x² - 13x + 36 = 0
                        (    )

x² - 8x + 16 = 0
                        (    )

x² - 7x + 12 = 0
                        (    )

x² + 10x + 21 = 0
                        (    )

x² + 15x + 56 = 0
                        (    )

                      +[    ]

x² + 5x + 6 = 0
                        (    )

x² - 14x + 48 = 0
                        (    )

x² - 5x + 6 = 0
                        (    )

x² - 15x + 54 = 0
                        (    )

x² - 9x + 20 = 0
                        (    )

x² - 10x + 24 = 0
                        (    )

x² + 11x + 28 = 0
                        (    )

x² + 15x + 56 = 0
                        (    )

x² - 5x + 6 = 0
                        (    )

x² - 12x + 35 = 0
                        (    )

                      +[    ]
                 +++[[       ]]