Answer
False;
The correct statement is:
$\dfrac{2^8}{2^{-3}} = 2^{11}$
Work Step by Step
RECALL:
$\dfrac{a^{m}}{a^n} = a^{m-n}, a\ne0$
Use the rule above to obtain:
$\dfrac{2^8}{2^{-3}} = 2^{8-(-3)}=2^{8+3}=2^{11}$
Thus, the given statement is false.
The correct statement is:
$\dfrac{2^8}{2^{-3}} = 2^{11}$