Slope, rate of change

Question

The linear function f(x)= -9.3x + 34 models the percentage of people, f(x), who eats at fast food restaurants each week x years after 1998. Find the slope and describe what it means in terms of rate of change of the dependent variable per unit of change in the independent variable. 

Answer 1

First, know that f(x) is a synonym for "y", the dependent variable.  You have y = mx +b.  (x is the independent variable.)

 

Slope m is the coefficient of x for this linear function.  m = slope = -9.3; for each unit of increase in x, the y decreases by 9.3 units.