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