# Math Help - negative exponents

1. ## negative exponents

Need some help again.

-2^-3 = ?

The answer in the book is -9/8

I thought it would be -1/8.

Jerry

2. $-2^{-3}$

$= -\frac {1}{2^3}$

$= -\frac {1}{8}$

The book is wrong.

3. ## Here you go

Originally Posted by Jerry Cunningham
Need some help again.

-2^-3 = ?

The answer in the book is -9/8

I thought it would be -1/8.

$a^{-b}=\frac{1}{a^{b}}$...therefore in this case since it is $-2^{-3}=\frac{1}{-2^3}=\frac{1}{-8}=\frac{-1}{8}$