Answer
$\dfrac{4}{5}$
Work Step by Step
RECALL:
(1) $a^0=1, a\ne 0$
(2) $a^{-m} = \dfrac{1}{a^m}$
(3) $a^1 = a$
Use the rules above to obtain:
$5^0-5^{-1}
\\=1 - \dfrac{1}{5^1}
\\=1 - \dfrac{1}{5}$
Since $1=\frac{5}{5}$, the expression above simplifies to:
$=\dfrac{5}{5} -\dfrac{1}{5}
\\=\dfrac{5-1}{5}
\\=\dfrac{4}{5}$
