The two graphs at right are y= x^2 - kx and y=3. Use the information given to solve the following equations for x.
x^2 -kx = 3
x^2 - kx = 0
In spite of substantial emphasis on viewing functions via multiple representations, students tend to have a favorite representation they revert to whenever possible. They often do not see the different representations of a function as carrying the same information and simply highlighting certain parts of it differently (e.g., x-intercepts).
Many students could not see how the graphs could help. Instead, students often attempted to solve the equation algebraically even though the given information is graphical.