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 ...

This graph shows 𝒚 = 2𝒙. The straight line shows the different values of 𝒙 and 𝒚 that follow the rule. For example, for the point (1, 2), the 𝒙 coordinate is 1 and the 𝒚 ...