You may travel outside México and should be familiar with currency conversion rates since currencies other than Mexican Pesos are used in most other countries. As of October 15, 2011, one US dollar was equivalent to 0.7749 Euros. A linear equation of a function, E, which converts US dollars (D) to Euros (E) would be E = 0.7749D
You would just put the number of dollars in for "D" and multiply by 0.7749 and this will give you the number of Euros you would get for your US dollars. This is a "real world application" of a linear function. Cell Phones
Just about everyone has a cell phone, and most rate plans are a linear function of some kind. Let's take a look at a basic example that is a real-life application of a linear equation. If you pay 20 dollars a month for your cell phone and 5 cents per minute of usage the monthly cost of using your cell phone would be a linear equation of a function, C, the monthly cost based on the number of minutes you use monthly. C = 0.05m + 20
You can see that your cost is 20 dollars plus five cents times the number of minutes you use your cell phone. Travel
Let's say we are going on a trip where we are averaging 60 miles per hour, this is a linear function. The equation would be D = 60t
where D is the distance covered in t hours. You would just put a time in hours in for t to see how far you get (D miles). You can see you don't have to look far for real-life examples of linears functions.
The linear function F = 1.8C + 32 can be used to convert temperatures between Celsius and Fahrenheit. If a utility company charges a fixed monthly rate plus a constant rate for each unit of power consumed, a linear function will show the monthly cost of power. If the fixed rate is $25, and the cost for each unit of power is $0.02, the linear function is C = 0.02P + 25. The linear function I = 400C + 1,500 yields the total monthly income of a car salesman who makes a monthly base salary of $1,500 and receives...