Answer
3
Work Step by Step
$27^{2/3}\cdot 27^{-1/3}=$ ...use: $a^{m}\cdot a^{n}=a^{m+n}$
$=27^{(2/3)+(-1/3)}$
$=27^{2/3-1/3}$
$=27^{1/3}=$ ... recognize: $27=3^{3}$
$=(3^{3})^{1/3}=$ ...use: $(a^{m})^{n}=a^{mn}$
$=3^{1}=3$