$\"\"$

The function is $\"f\\left$ .

Find $\"\"$ $\"f\\left$ .

Substitute $\"x=a\"$ in $\"f\\left$ .

$\"f\\left$ .

$\"\"$

Find $\"f\\left$ .

Substitute $\"x=a+h\"$ in $\"f\\left$ .

$\"f\\left$

$\"f\\left$ .

$\"\"$

Find $\"\\frac{f\\left$ .

Substitute the values of $\"f\\left$ and $\"f\\left$ .

$\"\\frac{f\\left$

$\"=\\frac{\\frac{a+4-(a+h+4)}{(a+h+4)(a+4)}}{h}\"$

$\"=\\frac{\\frac{a+4-a-h-4}{(a+h+4)(a+4)}}{h}=\\frac{\\frac{-h}{(a+h+4)(a+4)}}{h}\"$

$\"=\\frac{-1}{a^2+4a+ah+4h+4a+16}\"$

$\"\\frac{f(a+h)-f(a)}{h}=\\frac{-1}{a^2+ah+8a+4h+16}\"$ .

$\"\"$

$\"f\\left$ .

$\"f\\left$ .

$\"\\frac{f(a+h)-f(a)}{h}=\\frac{-1}{a^2+ah+8a+4h+16}\"$ .