х² - х - 6 = 0,
Д = 1 + 24 = 25,
х1 = (1 + 5) / 2*1 = 6/2 = 3,
х2 = (1 - 5) / 2*1 = -4/2 = -2,
3х² + 4х + 39 = 0,
Д = 16 + 468 = 484
х1 = (-4 + 22) / 2*3 = 18/6 = 3,
х2 = (-4 - 22) / 2*3 = -26/6 = - 4 1/3,
х² - 6х + 8 = 0,
Д = 36 - 32 = 4,
х1 = (6 + 2) / 2 * 1 = 8/2 = 4,
х2 = (6 - 2) / 2*1 = 4/2 = 2,
3х² + 8х + 5 = 0,
Д = 64 - 60 = 4,
х1 = (-8 + 2) / 2*3 = -6/6 = -1,
х2 = (-8 - 2) / 2/3 = -10/6 = -1 2/3,
4х² - 3х - 1 = 0,
Д = 9 + 16 = 25,
х1 = (3 + 5) / 2*4 = 8/8 = 1,
х2 = (3 - 5) / 2*4 = -2/8 = -1/4 (или -0,25),
х² + 3х + 18 = 0,
Д = 9 - 72 = -63,
корней нет,
4х² - 10х - 6 = 0,
Д = 100 + 96 = 196,
х1 = (10 + 14) / 2*4 = 24/8 = 3,
х2 = (10 - 14) / 2*4 = -4/8 = -1/2 (или -0,5),
5х² + 4х - 12 = 0,
Д = 16 + 240 = 256,
х1 = (-4 + 16) / 2*5 = 12/10 = 1 1/5 (или 1,2),
х2 = (-4 - 16) / 2*5 = -20/10 = -2
нет
Объяснение: