[ Eq(Derivative(x1, t), (1*k7*k1*x1*(1 - k2*x1) + (-1)*k7*k3*x1*x2)/k7),
  Eq(Derivative(x2, t), 1*k7*(k4*x2*(1 - k5*x2) + k6*x1*x2)/k7) ]