1) х² + 9х - 22 = 0
Д = 81 - 4 × 1 × (-22) = 81 + 88 = 169 > 0. 13
х1 = -9 + 13 / 2 = 4/2 = 2.
х2 = -9 - 13 / 2 = -22/2 = -11.
Ответ : -11 ; 2.
2) х² - 7х + 12 = 0
Д = 49 - 4 × 1 × 12 = 49 - 48 = 1 > 0. 1.
х1 = -7 + 1 / 2 = -6/2 = -3.
х2 = -7 - 1 / 2 = -8/2 = -4.
Ответ : -4 ; -3.
3) х² - х - 72 = 0
Д = 1 - 4 × 1 × (-72) = 1 + 288 = 289 > 0. 17.
х1 = 1 + 17 / 2 = 18/2 = 9.
х2 = 1 - 17 / 2 = -16/2 = -8.
Ответ : -8 ; 9.
Удачи)))))