3 different ways to show how the function f  links the input { 1,2, 3,4} to the output {2,4,6,8}

so f(x) = 2x       The “f of x” equals 2x.

The function f such that 1 maps to 5, 2 maps to 10 is described below :-

and  

Working backwards

Solution

This can be used to find the equation of a if two points have been given :

Example, find the equation of the line joining the points (1,5) and (3,11)

© Alexander Forrest