GCSE Edexcel Straight line graphs - Edexcel y = mx + c Graphs show the relationship between two variables and are often seen in newspapers and the media. People who work in professions involving ...

We use substitution to calculate the values. For example y = 2x + 1 The y value is always '2 lots' of the x value plus 1. We replace the value of x for different numbers and record the resulting y ...