input: Write a function to find the roots of a quadratic equation.
  assert find_roots(1, -3, 2) == (1.0, 2.0)
  assert find_roots(1, -2, 1) == (1.0, 1.0)
  assert find_roots(1, 0, -1) == (-1.0, 1.0)
output: def find_roots(a, b, c):
      import math
      discriminant = b**2 - 4*a*c
      root1 = (-b + math.sqrt(discriminant)) / (2*a)
      root2 = (-b - math.sqrt(discriminant)) / (2*a)
      return (root1, root2)