# Chapter 4 - Section 4.1 - Integer Exponents and Scientific Notation - 4.1 Exercises: 21

a. B. 1 b. C. -1 c. B. 1 d. C. -1

#### Work Step by Step

According to page 267, $a^{0}=1$ (where $a$ is a nonzero real number). In other words, we know that any nonzero real number raised to a power of 0 will equal 1. Therefore, a. $9^{0}=1$ b. $-9^{0}=-(9^{0})=-(1)=-1$ c. $(-9)^{0}=1$ d. $-(-9)^{0}=-(1)=-1$

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.