Final answer:
The equation that models the relationship between the total price for dry cleaning 3 pairs of pants is y = 18 + 6x. The constant proportionality is 6.
Step-by-step explanation:
The equation that models the relationship between the total price for dry cleaning 3 pairs of pants is given by y = 18 + 6x, where y represents the total price and x represents the number of pairs of pants. The constant proportionality is 6.
The y-intercept of the equation is 18, which represents the initial fee for dry cleaning. This means that even if no pants are cleaned, there is still a cost of $18.
The slope of the equation is 6, which means that for each additional pair of pants, the total price increases by $6. For example, if x = 1, then y = 18 + 6(1) = 24, indicating that the total price for 1 pair of pants would be $24.