{ diff(x1, t) = ((-1)*k3*k4*k5*x1*x2 + 1*k3*k6*x3 + (-1)*k3*k11*k12*k13*(x1/(1/4))^(9/25))/k3,
  diff(x2, t) = ((-1)*k3*k4*k5*x1*x2 + 1*k3*k6*x3 + (-1)*k3*k17*k18*k19*x5*x2 + 1*k3*1/20*k24*k25*k26*(x3/(1/4))^(9/25))/k3,
  diff(x3, t) = (1*k3*k4*k5*x1*x2 + (-1)*k3*k6*x3 + (-1)*k3*k7*k8*x3 + 1*k3*k9*k10*x4 + (-1)*k3*k21*k22*k23*(x3/(1/4))^(9/25) + (-1)*k3*k30*k31*k32*(x3/(1/4))^(9/25))/k3,
  diff(x4, t) = (1*k3*k7*k8*x3 + (-1)*k3*k9*k10*x4 + (-1)*k3*k14*k15*k16*x4)/k3,
  diff(x5, t) = (1*k3*k11*k12*k13*(x1/(1/4))^(9/25) + (-1)*k3*k17*k18*k19*x5*x2 + (-1)*k3*k20*x5 + 1*k3*1/200*k27*k28*k29*(x3/(1/4))^(9/25))/k3,
  diff(x6, t) = (1*k3*k14*k15*k16*x4 + 1*k3*k17*k18*k19*x5*x2 + 1*k3*k21*k22*k23*(x3/(1/4))^(9/25))/k3 }