2.4 Coordinates, linear and non-linear graphs
Represent equations and inequalities graphically and connect coordinates, gradients, intersections and function behaviour.
How to study WJEC GCSE Mathematics and Numeracy
Move from concept and notation to a justified method, show a complete mathematical chain, check scale and units, and interpret the answer in context.
Core concepts
Concept 1
Use four-quadrant coordinates and draw, recognise, sketch and interpret graphs.
Exam cue: Confirm the unit, entered tier, calculator condition and available formula list before choosing a method.
Concept 2
Use y = mx + c, line relationships and intersections to solve or model.
Exam cue: Mark scales and key points accurately, then interpret intercepts, intersections and gradients in mathematical terms.
Concept 3
Work with quadratic and other specified non-linear graphs, regions and simultaneous equations.
Exam cue: Show a complete mathematical chain, use correct notation and units, and interpret or check the result in its original context.
Concept 4
Current matrix coverage: Unit 2. Read the exact subpoint scope in each applicable unit column.
Concept 5
Foundation content is shown in standard type in the specification; bold additions apply only to Higher Tier.
Risk pitfalls and guardrails
Reading a graphical solution without stating which equation, intersection or boundary the coordinate satisfies.
Guardrail: Do not import the outgoing separate qualifications, assume a universal tier across units or ignore calculator, formula-list, context and accuracy conditions.
Assuming that every subpoint in a cross-unit strand appears in all three papers, rather than reading the correct matrix column.
Guardrail: Read the precise subpoint in the applicable unit column; a cross-unit strand does not mean every subpoint appears in every paper.
Using a Higher-only method or expectation for a Foundation entry, or importing the outgoing Mathematics/Mathematics-Numeracy structure.
Guardrail: Standard type applies to Foundation and Higher; bold specification additions are Higher-only. There is no Intermediate Tier.
Memory anchors
Gradient
Gradient measures vertical change divided by horizontal change.
Intercept
An intercept is where a graph crosses an axis.
Parallel lines
Distinct parallel straight lines have equal gradients.
Intersection
An intersection gives values satisfying both represented relationships.
Inequality region
A shaded region represents all coordinates satisfying the inequalities.
Checkpoint rule
Do the check-up only after you can summarize each concept in one sentence and identify one dangerous pitfall from memory.
Knowledge Check (after reading)
Short check-up to confirm understanding of this module.
Check-up Questions
Calculate the gradient of the line through (2,3) and (8,15).
For the straight line y=4x−7, what is y at x=3?
Answer all questions to submit.
Next step personalized recommendations
Continue learning
Move forward only after this module is stable.
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