Linear Functions

  1. What’s the slope of this line given by the equation \(y = 7+3x?\)
  2. What’s an equation of the line passing through the points \((-1,2)\) and \((9,-1)?\)
  3. What’s an equation for the line graphed in this plot?
  4. An entomologist suspects that the rate at which crickets chirp depends on the temperature in the crickets’ environment. Over the course of a few days in the field, she collects data, counting cricket chirps, and based on that data devises a function to model the number of cricket chirps-per-minute \(c(t)\) given the environmental temperature \(t\) (°F) as \[ c(t) = \frac{12t-52}{7}\,. \]
    1. How can you tell this function is linear, simply by referring to the form of the formula?
    2. What is the rate of change in chirps-per-minute per change in temperature? I.e. how many more chirps-per-minute will there be for every increase in temperature by 1°F?
    3. What does this rate of change mean within the context of the situation?
    4. What is the \(y\)-intercept of the graph of \(y = c(t)?\) What does this value mean within the context of the situation being modelled?
    5. This is the most important question of this activity; Come up with a well-thought-out response to it. Based on your analysis of the function \(c\) as a model for how often a cricket chirps given the temperature of the cricket’s environment, do you think it’s a “good” model? Why or why not?