**6. Conclusions**

The use of the Laplace transform in the study of Hyers–Ulam stability of differential equations is relatively recent (2013, see [7]). This method was not used to study the stability of equations with delay. In this paper, we have studied semi-Hyers–Ulam–Rassias stability and generalized semi-Hyers–Ulam–Rassias stability of Equations (1) and (5) using the Laplace transform. Some examples were given. The results obtained complete those of S. M. Jung and J. Brzdek from [13]. This method can be used successfully in the case of other equations with delay, integro-differential equations, partial differential equations or for fractional calculus. In [11], we have already studied a Volterra integro-differential equation of order I with a convolution type kernel and, in [12], the convection partial differential equation. In [20], the Poisson partial differential equation was studied via the double Laplace transform method. We intend to further study other equations.

**Funding:** This research received no external funding.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Not applicable.

**Conflicts of Interest:** The author declare no conflict of interest.
