Here's one example : a function representing an automobile's speed in mph - x - and its speed in ft per second - y
So.....some ordered pairs are :
x y
30 44
60 88
90 132
120 176
This is a linear function ......the slope is [ 88 - 44] / [ 60 - 30] = 44/30 = 22/15
And the equation of this function is
y - 44 = (22 / 15) (x - 30)
y = (22 / 15)x
Here's the graph : https://www.desmos.com/calculator/rjxubcceok
We know this is a function because it passes the vertical line test.....
