[ Eq(Derivative(x1, t), 1*k10*(k1*k2 - x1*(k3 + k4))/k10),
  Eq(Derivative(x2, t), 1*k10*(x1*k3 - x2*(k6 + k9) - k5*x2**2)/k10),
  Eq(Derivative(x3, t), 1*k10*(x2*k6 - x3*(k7 + k8))/k10) ]