“…However, the theory of impulsive functional differential equations is developing comparatively slowly due to numerous theoretical and technical difficulties caused by their peculiarities. In particular, to the best of our knowledge, there is little in the way of results for the oscillation of impulsive delay differential equations of neutral type despite the extensive development of the oscillatory and nonoscillatory properties of neutral differential equations without impulses (for example, see [5,6,2,3,7,[9][10][11][12]). In this paper, we consider the oscillation of all solutions of the following impulsive neutral delay differential equations with positive and negative coefficients, (1.1) and (1.2) reduce to the first-order neutral delay differential equations with positive and negative coefficients…”