Réponses

2013-03-02T12:03:05+01:00

AM² = 16 + x²

MF² = 9 + (3+4-x)² = 9 + (7-x)² = x² - 14x + 58

puisque AM = MF : x² - 14x + 58 = 16 + x² = -14x + 58 = 16 =>  -14x = 16 - 58 => -14x = -42

                                                                                                                            => x = 3