Math · Checkpoint 23 of 30 · Desmos · ~14 min
Graph, intersect, find zeros, build tables — the built-in calculator, from nothing.
The 30-second version
the Math section has a built-in Desmos graphing calculator. Type an equation → see its graph. Type two → tap where they cross to read the intersection. Gray points on the x-axis are the zeros. That's already enough to solve or check a large share of SAT Math questions. Practice inside Bluebook so you're using the exact testing version — don't assume every feature of the public Desmos site behaves identically there.
Open the calculator panel and type it exactly as written: y = 2x + 3, or a quadratic like y = x² − 5x + 6 (use the ^ key for powers). You don't need to rearrange into y= form for most equations — Desmos graphs relations like x² + y² = 25 directly.
To solve 2x + 3 = 11: enter y = 2x + 3 and y = 11 as two lines, then tap where they cross → (4, 11) → x = 4. This works for ugly equations exactly as easily as clean ones — that's the superpower.
Graph the function and tap the gray points where it meets the x-axis — those are the solutions of f(x) = 0. Tap the y-axis crossing for the y-intercept. For a quadratic, tap the vertex point for the max/min.
Enter both equations, tap the intersection, read (x, y). "What is x + y at the solution?" — just add the two numbers you're looking at.
Define f(x) = 3x² − 2x + 1, then type f(7) on a new line — Desmos prints the value. No plugging in by hand.
Add a table to see y-values at chosen x-values — handy for "which table represents the function?" questions: enter the function, type the table's x-values, compare.
You need the solutions of x² − 5x + 6 = 0. Fastest reliable Desmos route?
Graph it and tap: x = 2 and x = 3, in seconds, no algebra risk. (B works but does the job twice; C is simply false.) This exact pattern — quadratic equals zero, read the gray points — pays off many times per test.
The free web version of the graphing calculator built into Bluebook. Practice graphing equations, finding intersections, using tables, and running regressions in the same tool you'll have on test day.
A free Digital SAT channel whose standout feature is a complete, free Desmos course for SAT Math — a full playlist that teaches the graphing calculator step by step, from solving equations and systems to regressions, tables, and shortcuts, alongside general question walkthroughs.
Open a Bluebook practice module and force yourself to touch Desmos on every question where it could apply — speed comes from reps, not reading. Our full Desmos guide collects more walkthroughs.