у²-10у-24=0
Дискриминант D = (-10)² - 41(-24) = 100 + 96 = 196
y1,2 = (10 ± √196) / 2 = (10 ± 14) / 2
y1 = (10 + 14) / 2 = 24 / 2 = 12
y2 = (10 - 14) / 2 = -4 / 2 = -2
Ответ: y1 = 12, y2 = -2

3t²+7t+4=0
D = 7² - 434 = 49 - 48 = 1
t1,2 = (-7 ± 1) / 6
t1 = (-7 + 1) / 6 = -6 / 6 = -1
t2 = (-7 - 1) / 6 = -8 / 6 = -4/3
Ответ: t1 = -1, t2 = -4/3

2х²+9х-486=0
D = 9² - 42(-486) = 81 + 3888 = 3969
x1,2 = (-9 ± √3969) / 4
x1 = (-9 + 63) / 4 = 54 / 4 = 13.5
x2 = (-9 - 63) / 4 = -72 / 4 = -18
Ответ: x1 = 13.5, x2 = -18

9х²+6х+1=0
D = 6² - 491 = 36 - 36 = 0
x1,2 = -b / 2a = -6 / 18 = -1/3
Ответ: x1 = x2 = -1/3