x² + 11x + 28 = 0
                        ( -7 )

x² + 7x - 18 = 0
                        (    )

x² - 13x + 40 = 0
                        (    )

x² - 9 = 0
                        (    )

x² - 10x + 21 = 0
                        (    )

x² - 2x - 15 = 0
                        (    )

x² + x - 6 = 0
                        (    )

x² - 8x + 12 = 0
                        (    )

x² - x - 20 = 0
                        (    )

x² - x - 12 = 0
                        (    )

                      +[    ]

x² - 3x - 28 = 0
                        (    )

x² - 17x + 72 = 0
                        (    )

x² - 2x - 8 = 0
                        (    )

x² + 3x - 10 = 0
                        (    )

x² + 4x - 12 = 0
                        (    )

x² - 3x - 28 = 0
                        (    )

x² - 11x + 30 = 0
                        (    )

x² - 13x + 40 = 0
                        (    )

x² - 4 = 0
                        (    )

x² + x - 72 = 0
                        (    )

                      +[    ]

x² + x - 20 = 0
                        (    )

x² - 10x + 16 = 0
                        (    )

x² + 4x - 45 = 0
                        (    )

x² + 4x - 21 = 0
                        (    )

x² - 9 = 0
                        (    )

x² + 15x + 54 = 0
                        (    )

x² - 81 = 0
                        (    )

x² + 13x + 40 = 0
                        (    )

x² - 7x + 12 = 0
                        (    )

x² + 4x - 21 = 0
                        (    )

                      +[    ]
                 +++[[       ]]