Answer
$a)$ $f(x+h)=4x+4h+11$
$b)$ $f(x+h)-f(x)=4h$
$c)$ $\frac{f(x+h)-f(x)}{h}=4$
Work Step by Step
$a)$
$$f(x)=4x+11$$
Replace $x$ with $x+h$:
$$f(x+h)=4(x+h)+11$$
$$f(x+h)=4x+4h+11$$
$b)$
$$f(x+h)-f(x)$$
Substitute corresponding expressions:
$$4x+4h+11-(4x+11)$$
$$4x+4h+11-4x-11=4h$$
$c)$
$$\frac{f(x+h)-f(x)}{h}$$
Substitute corresponding expression for numerator:
$$\frac{4h}{h}=4$$
