Question

How do we get the answer?

Answer 1

$\frac{ {a}^{ - 3} }{ {a}^{2}.a}$

In the denominator as you can see that the bases are same, Therefore we're gonna add those powers.
something like this:
$= \frac{ {a}^{ - 3} }{ {a}^{2 + 1} } \\ = \frac{ {a}^{ - 3} }{ {a}^{3} }$

As we take the numerator to the denominator (when the base is same) then, the powers are turned to negative something like this:
$\frac{1}{ {x}^{3} } \\ = 1 \times {x}^{ -3} \\ = {x}^{ - 3}$


So we'll do the same thing here,
${a}^{ - 3} \times {a}^{ - 3}$
Bases are same so once again add the powers,
${a}^{ (- 3 ) + (- 3)}$

and you'll get :
${a}^{ - 6}$
which is the same thing as
$\frac{1}{ {a}^{6} }$