Mathematics — first biennium · Lesson
Substitution and elimination transform the system without changing its solution pair. After finding one variable, substitute it to find the other.
Prerequisites: Meaning of systems and linear equations
Goal: Solve 2×2 systems by substitution or elimination and verify the pair.
In this lesson: Solve 2×2 systems by substitution or elimination and verify the pair.
How to proceed: Try adding the equations when one variable cancels easily; then substitute the value found and check both sides of both equations.
You can already assume: Meaning of systems and linear equations.
Completed exercises: 0/5 · Correct on first attempt: 0
Try adding the equations when one variable cancels easily; then substitute the value found and check both sides of both equations.
Data / situation: 2x+y=-9; x−y=-3
ConceptStep separates what is required from what is recommended or useful as reinforcement. Only required prerequisites block your progress.
Relationships: solid line = required · dashed line = recommended · dotted line = reinforcement.