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