{ diff(x1, t) = ((-1)*k1*k2*x1 + 1*k1*k3*x2 + (-1)*k1*(k6*x1*x3 - k7*x6) + 1*k1*(k12*x7 - k13*x8*x1) + 1*k1*k24)/k1,
  diff(x2, t) = (1*k1*k2*x1 + (-1)*k1*k3*x2 + (-1)*k1*k25*x2)/k1,
  diff(x3, t) = ((-1)*k1*k4*x3 + 1*k1*k5*k26*x4 + (-1)*k1*(k6*x1*x3 - k7*x6) + (-1)*k1*x3*(k14*x3 + k15*x9) + 1*k1*k16*k26*x9 + 1*k1*k17*k26*x8 + 1*k1*k22)/k1,
  diff(x4, t) = (1*k1*k4*x3 + (-1)*k1*k5*k26*x4 + (-1)*k1*k23*x4)/k1,
  diff(x5, t) = 0,
  diff(x6, t) = (1*k1*(k6*x1*x3 - k7*x6) + (-1)*k1*x6*(k8*x6 + k9*x7) + 1*k1*k10*k26*x7/(k11 + x7))/k1,
  diff(x7, t) = (1*k1*x6*(k8*x6 + k9*x7) + (-1)*k1*k10*k26*x7/(k11 + x7) + (-1)*k1*(k12*x7 - k13*x8*x1))/k1,
  diff(x8, t) = (1*k1*(k12*x7 - k13*x8*x1) + (-1)*k1*k17*k26*x8)/k1,
  diff(x9, t) = (1*k1*x3*(k14*x3 + k15*x9) + (-1)*k1*k16*k26*x9)/k1,
  diff(x10, t) = ((-1)*k1*x10*(k18*x9 + k19*x7 + k20*x8) + 1*k1*k21*x11)/k1,
  diff(x11, t) = (1*k1*x10*(k18*x9 + k19*x7 + k20*x8) + (-1)*k1*k21*x11)/k1 }