Answer:
$80
Explanation:
If a person's monthly bill from the number of kilowatt-hours (kWh), x is modeled by the equation b = 0.15(x - 200) +20, to know the bill for a person who uses 600 kWh in a month, we will substitute x = 600 into the modeled equation as shown;
![b(x) = 0.15(x - 200) +20\\\\b(600) = 0.15(600 - 200) +20\\\\b(600 )= 0.15(400) +20\\\\b(600 )= 15/100*(400) +20\\\\b(600 )= (15*4)+20\\\\b(600 )= 60+20\\\\b(600 )= 80](https://img.qammunity.org/2021/formulas/mathematics/high-school/np0zb7bq3w7j7movc062j5yaubsxs68a67.png)
Hence the bill for a person who uses 600 kWh in a month is $80