Positive periodic solutions of neutral functional differential equations with a parameter and impulse

In this paper, we consider first-order neutral differential equations with a parameter and impulse in the form of $$displaylines{ frac{d}{dt}[x(t)-c x(t-gamma)]=-a(t)g(x(h_1(t)))x(t)+lambda b(t) fig(x(h_2(t))ig),quad t eq t_j;cr Delta ig[x(t)-c x(t-gamma)ig]=I_jig(x(t)ig),quad t=t_j,; jinmathbb{Z}^+. }$$ Leggett-Williams fixed point theorem, we prove the existence of three positive periodic solutions.