[ Eq(Derivative(x1, t), 0/k22),
  Eq(Derivative(x2, t), (1*1/k2*x1 + (-1)*1/k2*x2 + (-1)*k4*365/k9*(x3 + x7)/x1*x2 + (-1)*k7*365/k10*(x4 + x8)/x1*x2 + 1*1/k12*x5 + 1*1/k12*x6 + 1*1/k12*x9)/k22),
  Eq(Derivative(x3, t), ((-1)*1/k2*x3 + 1*k4*365/k9*(x3 + x7)/x1*x2 + (-1)*365/k9*x3)/k22),
  Eq(Derivative(x4, t), ((-1)*1/k2*x4 + 1*k7*365/k10*(x4 + x8)/x1*x2 + (-1)*365/k10*x4)/k22),
  Eq(Derivative(x5, t), ((-1)*1/k2*x5 + (-1)*(1 - k21)*k7*365/k10*(x4 + x8)/x1*x5 + 1*365/k9*x3 + (-1)*1/k12*x5)/k22),
  Eq(Derivative(x6, t), ((-1)*1/k2*x6 + (-1)*(1 - k21)*k4*365/k9*(x3 + x7)/x1*x6 + 1*365/k10*x4 + (-1)*1/k12*x6)/k22),
  Eq(Derivative(x7, t), ((-1)*1/k2*x7 + 1*(1 - k21)*k4*365/k9*(x3 + x7)/x1*x6 + (-1)*365/k9*x7)/k22),
  Eq(Derivative(x8, t), ((-1)*1/k2*x8 + 1*(1 - k21)*k7*365/k10*(x4 + x8)/x1*x5 + (-1)*365/k10*x8)/k22),
  Eq(Derivative(x9, t), ((-1)*1/k2*x9 + 1*365/k9*x7 + 1*365/k10*x8 + (-1)*1/k12*x9)/k22) ]