,
A rational expression is a fraction in which the numerator and/or the denominator are polynomials in this case we have
[tex]\frac{h}{h+4}+2[/tex]then need to have only one expression
[tex]\frac{h}{h+4}+\frac{2}{1}[/tex]In order to sum fractions we need to have the same denominator
[tex]\frac{h+2(h+4)}{h+4}[/tex]then we simplify the expression
[tex]\frac{h+2h+8}{h+4}[/tex]we sum like terms and we obtain the rational expression
[tex]\frac{3h+8}{h+4}[/tex]