In this paper, a discrete version of the well-known Montgomery's identity
is generalized, and a refinement of an inequality derived by B.G. Pachpatte in 2007 is presented. Finally, the results obtained are applied for expanding a complex multinomial formula in dfferent way of the classical
Popescu, P., Diaz-Barrero, J.L. New generalization of discrete Montgomery identity with applications. "RGMIA research report collection (Online y paper)", 2016, vol. 19, p. 1-6.