[ Eq(Derivative(x1, t), ((-1)*k5*(k7 + k8*k3) + 1*k4*k14*x2)/k4),
  Eq(Derivative(x2, t), (1*k5*(k7 + k8*k3) + (-1)*k6*k9*x2**2/(k10**2 + x2**2) + 1*k5*k3*x3*k1/k2*x2**4/(1 + k1/k2*x2**4)*k11*x4**2/(k12**2 + x4**2) + 1*k5*k13*x4 + (-1)*k4*k14*x2)/k5),
  Eq(Derivative(x3, t), ((-1)*k5*k15*x2**4*x3 + 1*k5*k16*(1 - x3))/k5),
  Eq(Derivative(x4, t), (1*k6*k9*x2**2/(k10**2 + x2**2) + (-1)*k5*k3*x3*k1/k2*x2**4/(1 + k1/k2*x2**4)*k11*x4**2/(k12**2 + x4**2) + (-1)*k5*k13*x4)/k6),
  Eq(Derivative(x5, t), (1*k5*k15*x2**4*x3 + (-1)*k5*k16*(1 - x3))/k5) ]