[ Diff(x[1], t) = (-1)*k[9]*k[1]*x[1]*ln(x[1]/x[2])*k[8]/k[9],
  Diff(x[2], t) = ((-1)*k[9]*k[2]*x[2]*k[8] + 1*k[9]*k[4]*x[1]*k[8] + (-1)*k[9]*k[5]*x[2]*x[1]^(2/3)*k[8] + (-1)*k[9]*k[6]*x[2]*x[3]*k[8])/k[9],
  Diff(x[3], t) = ((-1)*k[9]*k[3]*x[3]*k[8] + 1*k[9]*k[7])/k[9] ]