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: Samantha found the slope of the line that passed through the points
$${(2, 6)}$$
and
$${(-4, 8)}$$
. Her work is shown below.
$${{8-6\over {2-(-4)}} = {2\over 2+4 }= {2\over 6} = {1\over3}}$$
Samantha made an error in her work. Describe the error and then find the correct slope of the line through the two given points.


aligns: no