[ Eq(Derivative(x2, t), ((-1)*k23*k1/(1 + k2/x2*(1 + x3/k3)) + (-1)*k23*k4/(1 + 20000/(1 + 57/10*(x3/(x3 + 600))**2)*k6/(x2**2 + x2*k6)) + 1*k23*k17*k25*x5/(k20*k18 + k18*k25 + k19*x5 + k25*x5) + 1*k23*(7/10 - 1/40*(x3 + x4 - 150))*k21*x5/(k22 + x5) + 1*k23*k24*x1)/k23),
  Eq(Derivative(x3, t), (1*k23*k1/(1 + k2/x2*(1 + x3/k3)) + 1*k23*k4/(1 + 20000/(1 + 57/10*(x3/(x3 + 600))**2)*k6/(x2**2 + x2*k6)) + (-1)*k23*k10/(1 + 1*(1 + x4/4)/x3 + k12 + k12*1*(1 + x4/4)/x3) + (-1)*k23*k7/(1 + (k8/x3)**(23/10))*1/(1 + x4/k9))/k23),
  Eq(Derivative(x4, t), (1*k23*k10/(1 + 1*(1 + x4/4)/x3 + k12 + k12*1*(1 + x4/4)/x3) + 1*k23*k7/(1 + (k8/x3)**(23/10))*1/(1 + x4/k9) + (-1)*k23*k13*(x4 - k14*x5))/k23),
  Eq(Derivative(x5, t), (1*k23*k13*(x4 - k14*x5) + (-1)*k23*k17*k25*x5/(k20*k18 + k18*k25 + k19*x5 + k25*x5) + (-1)*k23*(7/10 - 1/40*(x3 + x4 - 150))*k21*x5/(k22 + x5) + (-1)*k23*(k15*(x3 + x4) - k16)*x5)/k23),
  Eq(Derivative(x6, t), 0),
  Eq(Derivative(x7, t), 1*k23*(k15*(x3 + x4) - k16)*x5/k23) ]