[ Diff(x[1], t) = ((-1)*k[9]*k[1]*(x[1] - x[2]) + 1*k[5]*x[2]*k[10] + (-1)*k[2]*x[2]^k[3]/(k[4]^k[3] + x[2]^k[3])*(x[1] - x[2])*k[9])/k[10],
  Diff(x[2], t) = (1*k[8]*k[9] + 1*k[9]*k[1]*(x[1] - x[2]) + (-1)*k[5]*x[2]*k[10] + 1*k[2]*x[2]^k[3]/(k[4]^k[3] + x[2]^k[3])*(x[1] - x[2])*k[9] + (-1)*k[6]*x[2]*k[11])/k[9] ]