1. f(x) = 3x⁴ - 2x⁷ + x - 1

  f'(x) = 12x³ - 14x⁶ + 1

2. f(x) = (x² - 1)(x² + 1) = x⁴ - 1

   f'(x) = 4x³

3. f(x) = (x³ - 4)/2x²

   f'(x) = ((x³ - 4)/x²)' * (1/2) = (3x²*x² - (x³ - 4)*2x / x⁴) * 1/2 = (3 - (x³ - 4)*2x / x⁴) / 2 = (3 - (x³ - 4)*2 / x³) / 2 = 1.5 - (x³ - 4) / x³