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: Write the formula for the functions depicted by the graphs below.
$${f(x)=}$$
$${g(x)=}$$
$${h(x)=}$$
[IMG]


aligns: no