Free public beta until December 4, 2026: every course is open, no card needed. After that, the first chapter of each course stays free and full access is a one-time $39 ($19 for up to 100 founding members chosen for helpful feedback). Your progress is kept. How the beta works

Create a free account to open Equations & inequalities. The free chapters of College Algebra stay readable without one.

average rate of change

Total change in output divided by total change in input over an interval.

The average rate of change of $f$ on $[a,b]$ is $\dfrac{f(b)-f(a)}{b-a}$ , the slope of the secant line through $(a,f(a))$ and $(b,f(b))$ .