Final answer:
The sale price of the dress can be calculated using the expression 0.75x. This represents a 25% discount on the original price.
Step-by-step explanation:
The sale price of the dress, represented in dollars, can be calculated using the expression 0.75x. This is because when the dress is on sale at a discount of 25%, the sale price will be 75% of the original price, which is equivalent to multiplying the original price by 0.75.
Thus, the correct expressions that represent the sale price of the dress are:
a. 0.75x
b. 0.75x