2.6 Simultaneous EquationsHigher Tier
The Eliminator
Simultaneous Equations — Elimination & Substitution Methods
Edexcel 4MA1 — Papers 1H & 2H
Panel A — Visual ToyInteractive
Panel B — Logic Track
Memory Rules
SSSSame Signs? Subtract
DSADifferent Signs? Add
The Goal
You can't solve for two unknowns at once. You must eliminate one to find the other.
Panel C — Dynamic SolverStep-by-step Mark Scheme Working
Worked Example:3x + 2y = 16and4x - 2y = 12
Identify
Eq1: 3x + 2y = 16 | Eq2: 4x - 2y = 12
Coefficients of y: +2 and -2. Different signs!
Rule Check
Different Signs → ADD (DSA)
Add Equations
(3x + 2y) + (4x - 2y) = 16 + 12
Back-substitute
Sub x = 4 into Eq1: 3(4) + 2y = 16
Gen Z Study — Edexcel 4MA1 Simultaneous Equations — The Eliminator