This app allows you to adjust the zeros of a quadratic function to match the factorization, then verify them with the general function. The examples include more challenging factorizations (a not equal to 1).

This app is an introduction to the idea of residual plots which help interpret the accuracy of a line of fit by making the pattern in the residuals easier to see. An apparently linear data set is used to show how important the residual plot is. (S-ID 6b)

This app allows you to experiment with a movable line on a given data set to find the placement with the smallest possible magnitude for the sum of the residuals. (S-ID 6b)