The given function is:
[tex]\begin{gathered} f(x)=2x-5 \\ f(x+h)=2(x+h)-5=2x+2h-5 \end{gathered}[/tex]So the expression is evaluated as follows:
[tex]\begin{gathered} \frac{f(x+h)-f(x)}{h}=\frac{2x+2h-5-(2x-5)}{h} \\ =\frac{2x+2h-5-2x+5}{h} \\ =\frac{2h}{h} \\ =2 \end{gathered}[/tex]So the value of the expression is 2.