[ Eq(Derivative(x1, t), 0/k13),
  Eq(Derivative(x2, t), (1*k13*k1*x2*(1 - (x2 + x3)/k3) + (-1)*k13*(k4 + (1/2 + x1**2/(5**2 + x1**2))*k10/(k10 + x5**2))*x2)/k13),
  Eq(Derivative(x3, t), (1*k13*k2*x3*(1 - (x2 + x3)/k3) + (-1)*k13*(k4 + k7*x4**2/(k8 + x4**2))*x3)/k13),
  Eq(Derivative(x4, t), (1*k13*k5*x2 + (-1)*k13*(k11 + k4)*x4)/k13),
  Eq(Derivative(x5, t), (1*k13*(1/50 + 3/100*x1**2/(5**2 + x1**2))*x3 + (-1)*k13*(k12 + k4)*x5)/k13),
  Eq(Derivative(x6, t), 0),
  Eq(Derivative(x7, t), 0) ]