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