[ Eq(Derivative(x1, t), ((-1)*k12*k1*x1 + 1*k12*k10)/k12),
  Eq(Derivative(x2, t), (1*k12*k1*x1 + (-1)*k12*k2*x2)/k12),
  Eq(Derivative(x3, t), (1*k12*k2*x2 + (-1)*k12*k3*x3)/k12),
  Eq(Derivative(x4, t), (1*k12*k3*x3 + (-1)*k12*k4*x4)/k12),
  Eq(Derivative(x5, t), (1*k12*k4*x4 + (-1)*k12*k5*x5)/k12),
  Eq(Derivative(x6, t), (1*k12*k5*x5 + (-1)*k12*k6*x6)/k12),
  Eq(Derivative(x7, t), (1*k12*k6*x6 + (-1)*k12*k7*x7)/k12),
  Eq(Derivative(x8, t), (1*k12*k7*x7 + (-1)*k12*k8*x8)/k12),
  Eq(Derivative(x9, t), ((-1)*k12*k9*x9 + 1*k12*k8*x8)/k12) ]