Recall that to evaluate a function, we have to substitute the variable by the given value, in this case, the given value is
[tex]x+h\text{.}[/tex]Evaluating the given function at x+h, we get:
[tex]2(x+h)+3,[/tex]applying the distributive law, we get:
[tex]2x+2h+3.[/tex]Now we subtract f(x) from the above expression
[tex]2x+2h+3-(2x+3)\text{.}[/tex]Simplifying the above expression, we get:
[tex]2h\text{.}[/tex]Answer:
[tex]2h\text{.}[/tex]