GraphPrep teaches you to use the Desmos calculator — the most powerful tool on the SAT & ACT — to solve any problem, step by step.
The function g is defined by g(x) = |x|/a − 14, where a < 0. What is the product of g(15a) and g(7a)?
Use a slider for the unknown constant a to verify the result stays constant for any negative value.
Why GraphPrep
Paste any SAT or ACT math problem and get an instant, personalized Desmos walkthrough — not just the answer.
Paste any problem and get a step-by-step Desmos strategy in seconds — no manual setup required.
Follow numbered steps that teach you exactly what to type into Desmos and why it works.
Switch to Hands-On mode and enter the expressions yourself, with hints when you need them.
How it works
From problem to understanding in under a minute.
Type or paste any SAT/ACT math question — or snap a photo. GraphPrep reads it instantly.
Get a tailored walkthrough: which expressions to enter, what to look for, and why it works.
Replay in Hands-On mode until the technique sticks — so you can do it solo on test day.
Pricing
No credit card needed to get started. Upgrade when you want 300 problems a month.
Free
forever
Perfect for trying it out before your next practice test.
Pro
/ month · cancel anytime
For students serious about hitting their target score. ~10 problems/day.