[ Eq(Derivative(x1, t), (-1)*k31*k29*exp(k30*t)*x1/k31),
  Eq(Derivative(x2, t), ((-1)*k31*k29*exp(k30*t)*x2 + 1*k31*k29*exp(k30*t)*x1)/k31),
  Eq(Derivative(x3, t), (1*k31*k29*exp(k30*t)*x2 + (-1)*k31*k29*exp(k30*t)*x3)/k31),
  Eq(Derivative(x4, t), (1*k31*k29*exp(k30*t)*x3 + (-1)*k31*k29*exp(k30*t)*x4)/k31),
  Eq(Derivative(x5, t), (1*k31*k29*exp(k30*t)*x4 + (-1)*k31*k29*exp(k30*t)*x5)/k31),
  Eq(Derivative(x6, t), (1*k31*k29*exp(k30*t)*x5 + (-1)*k31*k29*exp(k30*t)*x6)/k31),
  Eq(Derivative(x7, t), (1*k31*k29*exp(k30*t)*x6 + (-1)*k31*k29*exp(k30*t)*x7)/k31),
  Eq(Derivative(x8, t), (1*k31*k29*exp(k30*t)*x7 + (-1)*k31*k29*exp(k30*t)*x8)/k31),
  Eq(Derivative(x9, t), 1*k31*k29*exp(k30*t)*x8/k31) ]