Laplace transformation will be applied to calculate differential equation of the second row → y'+y=-3. Differential equation has initial conditions y(0)=0, and y'(0)=0. Laplace transformation form Y(s) of function y(t) will be calculated. Function in form Y(s) will be smashed to simple fractions. In the last step inverse transformation on function Y(s) will be executed to find function y(t), which is in domain of time. During execution of inverse Laplace transformation, formulas for Laplace transformations of basic function will be applied.