Answer:
[tex]\frac{1}{a(a-4)}[/tex]
Step-by-step explanation:
Factor the denominator of the first fraction
a² - 16 ← is a difference of squares and factors as
a² - 16 = (a - 4)(a + 4), thus fraction becomes
[tex]\frac{a}{(a-4)(a+4)}[/tex] × [tex]\frac{a+4}{a^2}[/tex]
Cancel the factor (a + 4) on numerator/denominator and the a and a², leaving
[tex]\frac{1}{a(a-4)}[/tex]