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Digital SAT Desmos Regression & Graphing Lab

Desmos Superpowers & Math Hacks

Master the top 10 Desmos techniques that allow you to solve 70%+ of Digital SAT Math questions in under 20 seconds without factoring, algebra systems, or completing the square.

Average Time Saved Per Test
~18 Minutes
Unlocks 780–800 SAT Math Target
Hack #1 • Advanced Math

Table Regression for Unknown Polynomials

When given 3 points on a parabola and asked for its equation or vertex, NEVER use a 3-variable linear system.

Save 90 Seconds
Target SAT Math Question:
A parabola passes through (1,6)(1, 6), (3,16)(3, 16), and (5,34)(5, 34). What is the value of f(7)f(7)?
❌ The Slow Algebraic Way (2+ Mins)
Set up a(1)2+b(1)+c=6a(1)^2 + b(1) + c = 6, a(9)+b(3)+c=16a(9) + b(3) + c = 16, a(25)+b(5)+c=34a(25) + b(5) + c = 34 and solve by elimination (takes ~2.5 minutes).
⚡ The Desmos Shortcut (15 Seconds)
Insert a Table with columns x1x_1 and y1y_1. Enter the 3 points. In line 2, type the regression equation: y1∼ax12+bx1+cy_1 \sim a x_1^2 + b x_1 + c. Desmos instantly outputs a=1,b=2,c=3a=1, b=2, c=3. Then type 1(7)2+2(7)+3=661(7)^2 + 2(7) + 3 = 66.
Exact Desmos Input to Copy:
y_1 ~ a*x_1^2 + b*x_1 + c
Why this works: The tilde symbol (~) instructs Desmos to perform a continuous least-squares regression matching the parameters $a, b, c$ to your table points in 0.01 seconds.

Live Desmos Graphing Sandbox

Official Test Version