[ Diff(x[1], t) = ((-1)*x[1]*k[8]*k[3]*k[2] + (-1)*x[1]*x[4]*k[4]*k[2] + 1*x[3]*k[7]*k[2])/k[2],
  Diff(x[2], t) = 0,
  Diff(x[3], t) = (1*k[8]*x[4]*k[5]*k[2] + (-1)*x[3]*k[7]*k[2])/k[2],
  Diff(x[4], t) = (1*x[1]*k[8]*k[3]*k[2] + (-1)*x[1]*x[4]*k[4]*k[2] + 1*k[8]*x[4]*k[5]*k[2] + (-2)*x[4]^2*k[6]*k[2])/k[2],
  Diff(x[5], t) = 0 ]