Ответ:

1)

x1 = (-b - (b**2 - 4 * a * c)**(1/2)) / (2 * a)

x2 = (-b + (b**2 - 4 * a * c)**(1/2)) / (2 * a)

2)

import math  

y = 1 + (x / math.factorial(1)) + (x**2 / math.factorial(2)) + (x**3 / math.factorial(3))