Edexcel IGCSE Maths

Revision Notes

3.10.1 Solving Equations using Graphs

How do we use graphs to solve equations?

  • Solutions are always read off the x-axis
  • Solutions of f(x) = 0 are where the graph of y = f(x) cuts the x-axis
  • If given g(x)=0 instead (Q: “by drawing a suitable straight line”) then:
    • Rearrange into f(x) = mx + c and draw the line y = mx + c
    • Solutions are the x-coordinates of where the line crosses the curve
      Note that solutions may also be called roots

Worked Example

Solving equations using graphs Worked Example 1, downloadable IGCSE & GCSE Maths revision notes

Cubic-Linear-Intersections-(before), IGCSE & GCSE Maths revision notes

Solving equations using graphs Worked Example 2, downloadable IGCSE & GCSE Maths revision notes

Cubic-Linear-Intersections-(after), IGCSE & GCSE Maths revision notes

Solving equations using graphs Worked Example 3, downloadable IGCSE & GCSE Maths revision notes

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