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