Question

Consumers Energy states that the average electric bill across the state is $39.09. You want to test the claim that the average bill amount is actually different from $39.09. What are the appropriate hypotheses for this test

Answer 1

The null hypothesis is $\mu = 39.09$  

The symbol $\mu$ is the Greek letter mu

The alternate hypothesis is $\mu \ne 39.09$ telling us we have a two-tailed test here. The "not equal" is directly tied to the keyword "different" given in the instructions. In other words, mu being different from 39.09 directly leads to $\mu \ne 39.09$

So either mu is 39.09 or it's not 39.09

You can use H0 and H1 to represent the null and alternate hypotheses respectively.  

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Summary:

The two hypotheses are

H0: $\mu = 39.09$

H1: $\mu \ne 39.09$

This is a two tailed test.