Final answer:
The equation that represents the highest and lowest prices for which the dealer might sell the motorcycle is 21,000 ≤ x ≤ 24,000, with x being the selling price.
Step-by-step explanation:
The average selling price of a certain type of motorcycle is $22,500. The dealer allows this price to vary by $1,500. To represent the highest and lowest prices for which the dealer might sell the motorcycle, you can use the variable 'x'. The highest price can be expressed as x = $22,500 + $1,500, which equals $24,000. The lowest price can be written as x = $22,500 - $1,500, which equals $21,000. Therefore, the equation that represents the highest and lowest prices for which the dealer might sell the motorcycle is:
21,000 ≤ x ≤ 24,000