standard_description: Interpret the equation y = mx + b as defining a linear function, whose graph is a straight line; give examples of functions that are not linear. For example, the function A = s2 giving the area of a square as a function of its side length is not linear because its graph contains the points (1,1), (2,4) and (3,9), which are not on a straight line.
problem_activity: Task
Pictured below are the graphs of four different functions, defined in terms of eight constants:  $a, b, c, k, m, p, q, \text{ and } r.$  The equations of the functions are:
$y=mx+b$
$y=a\cos(x)+c$
$y=qr^x$
$y=kx^p$
[IMG]
Match each equation with its graph.
Use the graphs to answer the following questions.  Justify your answers with appropriate explanations.
Which of the 8 constants are definitely negative?
Which of the 8 constants are definitely positive?
Which of the 8 constants are  definitely greater than zero but less than one?
Which of the 8 constants are definitely greater than one?


aligns: no