C = \dfrac{-1}{2} + \dfrac{3}{21} + \dfrac{-2}{6} + \dfrac{-5}{30}
C = \dfrac{-1}{2} + \dfrac{1}{7} + \left ( \dfrac{-10}{30} + \dfrac{-5}{30} \right )
C = \dfrac{-1}{2} + \dfrac{1}{7} - \dfrac{1}{2}
C = -1 + \dfrac{1}{7} = \dfrac{-6}{7}
H = 17,5.(-121,1) + 17,5. 21,1 = 17,5(-100 - 21,1) +...