[ x[6] = k[13] - x[5],
  x[8] = x[7] - x[11],
  x[10] = x[9] - x[11],
  x[16] = x[14] - x[15],
  x[18] = k[42] - x[17],
  x[20] = k[50] - x[19],
  x[22] = (1 + k[51]*k[52]*x[10])/(1 + k[52]*x[10])*k[53],
  x[23] = k[28] - x[12] - x[13],
  x[24] = k[29] - x[13] ]