Let's set d as the age of Davon and m as the age of Milan.
Devon is 30 years old than his son Milan, it is represented by the equation:
[tex]d=m+30\text{ Equation (1)}[/tex]The sum of both ages is 56, the equation that represents the situation is:
[tex]d+m=56\text{ Equation (2)}[/tex]To find Devon's age, in equation 1, solve for m in terms of d:
[tex]m=d-30[/tex]Now, replace in equation 2 and solve for d:
[tex]\begin{gathered} d+(d-30)=56 \\ 2d-30=56 \\ 2d=56+30 \\ 2d=86 \\ d=\frac{86}{2} \\ d=43 \end{gathered}[/tex]Devon is 43 years old.