To complete the perfect trinomial, we add (5/2)² to the given equation and get:
[tex]x^2+5x+(\frac{5}{2})^2+6=(\frac{5}{2})^2.[/tex]Subtracting 6 we get:
[tex]x^2+5x+(\frac{5}{2})^2=\frac{25}{4}-6=\frac{1}{4}.[/tex]Therefore:
[tex](x+\frac{5}{2})^2=\frac{1}{4}.[/tex]Finally, we get:
[tex]\begin{gathered} x+\frac{5}{2}=\pm\sqrt{\frac{1}{4}}, \\ x=\pm\frac{1}{2}-\frac{5}{2}. \end{gathered}[/tex]