Evaluate f(-1)=5^-1

$f (- 1) = 5^{- 1}$

Move $- 1$ to the left of $f$ .

$- 1 f = 5^{- 1}$

Rewrite $- 1 f$ as $- f$ .

$- f = 5^{- 1}$

Rewrite the expression using the negative exponent rule $b^{- n} = \frac{1}{b^{n}}$ .

$- f = \frac{1}{5}$

The result can be shown in multiple forms.

Exact Form:

$- f = \frac{1}{5}$

Decimal Form:

$- f = 0.2$