[ Eq(Derivative(x1, t), ((-1)*k2*x12*x1*k13 + (-1)*k6*x1*k13 + 1*k7*x2*k13)/k13),
  Eq(Derivative(x2, t), (1*k6*x1*k13 + (-1)*k7*x2*k13)/k13),
  Eq(Derivative(x3, t), (1*k2*x12*x1*k13 + (-1)*k3*x3*x7*k13)/k13),
  Eq(Derivative(x4, t), (1*k3*x3*x7*k13 + (-1)*k4*x4*k13)/k13),
  Eq(Derivative(x5, t), (1*k4*x4*k13 + (-1)*k5*x5*k13)/k13),
  Eq(Derivative(x6, t), ((-1)*k8*x6*x3*k13 + (-1)*k8*x6*x4*k13 + 1*k9*x7*x8*k13)/k13),
  Eq(Derivative(x7, t), (1*k8*x6*x3*k13 + 1*k8*x6*x4*k13 + (-1)*k9*x7*x8*k13)/k13),
  Eq(Derivative(x8, t), 0/k13),
  Eq(Derivative(x9, t), ((-1)*k10*x9*x7*k13 + 1*k11*x10*x8*k13)/k13),
  Eq(Derivative(x10, t), (1*k10*x9*x7*k13 + (-1)*k11*x10*x8*k13)/k13),
  Eq(Derivative(x11, t), 1*x10*k12*k13/k13) ]