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Quick reference: all techniques at a glance
Before diving into each technique in detail, here is the complete Desmos SAT cheat sheet at a glance. Every technique, what to type, what to look for.
| Technique | What to type in Desmos | What to read | Time saved |
|---|---|---|---|
| Intersection points | Eq 1 on line 1, Eq 2 on line 2 | Click the intersection dot | 2 min → 15 sec |
| Vertex of a parabola | y = ax² + bx + c | Click the bottom/top grey dot | 90 sec → 10 sec |
| Zeros of a quadratic | y = ax² + bx + c | Click the x-intercept grey dots | 60 sec → 10 sec |
| Circle center | Equation as written (any form) | Midpoint of top and bottom | 3 min → 20 sec |
| Slider for constants | Equation with k — click "add slider" | Drag until lines overlap/parallel | 2 min → 30 sec |
| Inequality region | Each inequality on separate line | Overlapping shaded region | 90 sec → 15 sec |
| Regression | Table + y&sub1; ~ mx&sub1; + b | m and b values shown | 2 min → 30 sec |
| Back-solving | Type each answer choice | Which one satisfies the equation | 60 sec → 20 sec |
| Statistics on a list | [val1, val2, val3, ...] | mean(), median(), stdev() | 45 sec → 10 sec |
Technique 1: Intersection points
When to use it: Any question asking where two equations meet, what value satisfies both equations, or the solution to a system. This is the single highest-value Desmos technique on the SAT — it applies to a larger share of questions than any other technique.
$|x - 5| = -|x - 5| + 14$
What is the sum of the solutions to the given equation?
Works for: linear systems, mixed linear and quadratic systems, absolute value equations, exponential equations, any "for what value of x does..." question.
Pro tip: You do not need to rearrange to slope-intercept form. Desmos accepts standard form, implicit form, and point-slope form directly. Type the equation exactly as written in the question.
Technique 2: Vertex and zeros of quadratics
When to use it: Any quadratic question asking for the vertex, maximum, minimum, axis of symmetry, x-intercepts, or zeros. Desmos finds all of these instantly by clicking grey dots on the graph.
What appears: Desmos marks the vertex and x-intercepts as grey dots automatically. Click any dot to read exact coordinates. No completing the square, no −b/2a formula, no quadratic formula required.
The solutions to $x^2 + 6x + 7 = 0$ are $r$ and $s$, where $r < s$. The solutions to $x^2 + 8x + 8 = 0$ are $t$ and $u$, where $t < u$. The solutions to $x^2 + 14x + c = 0$ are $r+t$ and $s+u$. What is the value of $c$?
Pro tip: The vertex y-coordinate IS the minimum value (for upward parabola) or maximum value (for downward parabola). One click gives you both the axis of symmetry and the extreme value simultaneously.
Technique 3: Circles in any form
When to use it: Any circle question asking for center coordinates or radius — especially when the equation is in expanded form that would require completing the square twice to solve algebraically.
$x^2 - 12x + y^2 + 6y = 5$
The equation above defines a circle in the $xy$-plane. What are the coordinates of the center of the circle?
Pro tip: Desmos graphs ANY circle equation directly — standard form, general form, expanded form. You never need to rearrange or complete the square first.
Technique 4: Sliders for constants
When to use it: Questions that ask for what value of a constant k makes a system have zero solutions, one solution, or infinitely many solutions. These are abstract algebra questions that become visual with Desmos.
$3x + 21 = b(x + 7)$
In the given equation, $b$ is a constant. If the equation has infinitely many solutions, what is the value of $b$?
What to look for: Parallel lines = no solution. Overlapping lines = infinitely many solutions. Lines touching at one point = exactly one solution.
Technique 5: Inequality regions
When to use it: Questions about solution regions for a system of inequalities — which area of the graph satisfies all conditions simultaneously.
$3x > 9$
$y > 4x - 2$
Which of the following consists of the $y$-coordinates of all the points that satisfy the system of inequalities above?
Pro tip: For strict inequalities (> or <) the boundary is a dashed line. For non-strict (≥ or ≤) it is solid. Desmos handles this automatically.
Techniques 6 to 9: quick reference
Each dot in a scatterplot represents the flipper length $x$ (cm) and swim speed $y$ (km/h) of one penguin in a study of 15 penguins. The graph of which of the following equations is a line that most closely fits the data?
Use the tilde (~) not equals (=). The tilde tells Desmos to find the best-fit values — this is the regression command. Works for linear, quadratic, and exponential models.
$3x + 4y = 8$
$9x + 12y = 24$
For each real number $r$, which of the following points lies on the graph of each equation in the $xy$-plane for the given system?
Converts a "solve" question into a "verify" question. Works on approximately 30% of SAT math questions. Especially useful when the algebraic approach involves messy fractions or multiple steps.
The median and the mean of the five integers $\{10, 12, 26, x, x\}$ are equal. What is the sum of all possible values of $x$?
Faster and more reliable than manual calculation, especially with large datasets or when the SAT question gives you many data points.
Turns a factoring or simplification question into a visual matching task. If two expressions are equivalent, their graphs are identical. Note: watch for domain restrictions — Desmos shows holes that may differ between expressions.
When NOT to use Desmos — the most important section
Most Desmos cheat sheets skip this section entirely. It is the most strategically important one for students targeting 1400 or above.
Skip Desmos in these situations
Want 57 problems with every technique applied?
SAT Desmos Hacks: The EPIC Method for Smart, Fast, 800-Level Math 2026 by Jaclyn Caruana is the only published SAT math book built entirely around the Desmos graphing calculator. 245 pages, full color, 57 original SAT-style problems across all four domains — every problem with a step-by-step solution and a real Desmos screenshot.
SAT Desmos Hacks: The EPIC Method
for Smart, Fast, 800-Level Math 2026
By Jaclyn Caruana · Epic Exam Prep · ISBN 9798246911198 · 245 pages · Full color · 57 original problems. Companion practice site at desmos.prepdrills.com included with purchase.
See Desmos SAT techniques in action on YouTube
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