This key facts covers Two Methods within Simultaneous Equations for GCSE Mathematics. Revise Simultaneous Equations in Algebra for GCSE Mathematics with 15 exam-style questions and 12 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 2 of 8 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Two Methods
| Method | When to Use | How It Works |
|---|---|---|
| Elimination | Coefficients match or can be made to match | Add or subtract equations to cancel one variable |
| Substitution | One equation already has x= or y= | Replace variable in second equation |
Practice questions for Simultaneous Equations
Which method is most efficient for solving the following simultaneous equations? 5x + 2y = 14 3x + 2y = 10
Ali solves the simultaneous equations 5x + y = 17 and x - y = 1 by elimination. Ben says he can also use substitution by rearranging x - y = 1 to get x = y + 1. Explain how elimination works for these two equations and state one advantage of Ben's substitution approach.