A local festival is selling pies. Customers can buy apple pies and pumpkin pies, Apple pies are sold for \( \$ 5 \) each and pumpkin pies are sold for \( \$ 7 \) each. which equation represents. the total amount of money spent on pies lay customers.
A linear function that models data is described below. Find the slope of the model. Then describe what this means in terms of the rate of change of the dependent variable per unit change in the independent variable. The linear function \( f ( x ) = - 0.41 x + 28.6 \) models the percentage of adults in a country who smoked cigarettes, \( f ( x ) \) , \( x \) years after \( 1997 \) .
The slope is \( \square \) . (Type an integer or a decimal.)