[ Eq(Derivative(x1, t), ((-1)*k15*k17*x11*x1/(k1 + x1) + 1*k15*k18*x2*x9/k2/(1 + x2/k2 + x1/k11 + x5/k5 + x4/k6 + x3/k11))/k15),
  Eq(Derivative(x2, t), (1*k15*k17*x11*x1/(k1 + x1) + (-1)*k15*k18*x2*x9/k2/(1 + x2/k2 + x1/k11 + x5/k5 + x4/k6 + x3/k11))/k15),
  Eq(Derivative(x3, t), ((-1)*k15*k19*x2*x3/k3/(1 + x3/k3 + x4/k4) + 1*k15*(k23*x9*x4/k6/(1 + x2/k2 + x1/k11 + x5/k5 + x4/k6 + x3/k11) + k24*x10*x4/k14/(1 + x5/k13 + x4/k14 + x3/k12 + x6/k12 + x7/k10 + x8/k9)))/k15),
  Eq(Derivative(x4, t), (1*k15*k19*x2*x3/k3/(1 + x3/k3 + x4/k4) + (-1)*k15*k20*x2*x4/k4/(1 + x3/k3 + x4/k4) + 1*k15*(k21*x9*x5/k5/(1 + x2/k2 + x1/k11 + x5/k5 + x4/k6 + x3/k11) + k22*x10*x5/k13/(1 + x5/k13 + x4/k14 + x3/k12 + x6/k12 + x7/k10 + x8/k9)) + (-1)*k15*(k23*x9*x4/k6/(1 + x2/k2 + x1/k11 + x5/k5 + x4/k6 + x3/k11) + k24*x10*x4/k14/(1 + x5/k13 + x4/k14 + x3/k12 + x6/k12 + x7/k10 + x8/k9)))/k15),
  Eq(Derivative(x5, t), (1*k15*k20*x2*x4/k4/(1 + x3/k3 + x4/k4) + (-1)*k15*(k21*x9*x5/k5/(1 + x2/k2 + x1/k11 + x5/k5 + x4/k6 + x3/k11) + k22*x10*x5/k13/(1 + x5/k13 + x4/k14 + x3/k12 + x6/k12 + x7/k10 + x8/k9)))/k15),
  Eq(Derivative(x6, t), ((-1)*k15*k25*x5*x6/k7/(1 + x6/k7 + x7/k8) + 1*k15*k28*x10*x7/k10/(1 + x5/k13 + x4/k14 + x3/k12 + x6/k12 + x7/k10 + x8/k9))/k15),
  Eq(Derivative(x7, t), (1*k15*k25*x5*x6/k7/(1 + x6/k7 + x7/k8) + (-1)*k15*k26*x5*x7/k8/(1 + x6/k7 + x7/k8) + 1*k15*k27*x10*x8/k9/(1 + x9/k13 + x4/k14 + x3/k12 + x6/k12 + x7/k10 + x8/k9) + (-1)*k15*k28*x10*x7/k10/(1 + x5/k13 + x4/k14 + x3/k12 + x6/k12 + x7/k10 + x8/k9))/k15),
  Eq(Derivative(x8, t), (1*k15*k26*x5*x7/k8/(1 + x6/k7 + x7/k8) + (-1)*k15*k27*x10*x8/k9/(1 + x9/k13 + x4/k14 + x3/k12 + x6/k12 + x7/k10 + x8/k9))/k15),
  Eq(Derivative(x9, t), 0/k15),
  Eq(Derivative(x10, t), 0/k15),
  Eq(Derivative(x11, t), 0/k15) ]