The average rate of change for a given function from point a to point b is computed as follows:
[tex]\frac{f(b)-f(a)}{b-a}[/tex]In this case:
• f(x) = 3x + 4
,• b = 5 + h
,• a = 5
[tex]\frac{3(5+h)+4\text{ - ( 3(5) + 4)}}{5+h\text{ - 5}}=\frac{15+3h+4\text{ - 15 - 4}}{h}=\frac{3h}{h}=\text{ 3}[/tex]