SOLUTION: I would like to know how I could show a real-life example of a linear function.

You can put this solution on YOUR website!
You can rent an electricity generator for $4.80 per hour plus $100.00 for a full tank of petrol.
Let y represent the cost of using the generator.
Let x represent the hours.
The cost is $4.80 per hour plus $100.00 for a the petrol tank.
Translate the statement to an equation.
y = 100.00 + 4.80x
f(x) = 100.00 + 4.80x
Lets choose 6 for the hours,
substitute 6 for x.
f(6) = 100.00 + 4.80(6)
f(6) = 100.00 + 28.80 = 128.80
So, the cost of renting the generator for 6 hours is $128.80
:)