College Algebra Tutorial on Linear Equations in One Variable

A linear equation produces a straight line when graphed. Some equations contain just a single variable (an unknown like x or y). In college algebra, you’ll need to know how to graph linear equations of one variable. Graphing in college algebra is usually accomplished on a graphing calculator, but you’ll also need to know how to interpret the results from those graphs.

Instructions

1. Enter the Y Editor on your calculator. Most graphing calculators will have a “Y=” button that you can press to enter the editor.

2. Enter the expression using the alphanumeric keypad, without typing the “Y=.” For example, y= 2x + 2 would be entered on the calculator as 2x + 2. (The ^ symbol normally has its own key.)

3. Graph the equation. Most graphing calculators have a “Graph” button.

4. Press the “Trace” button on your calculator. This slides along the length of the graph, giving you every possible output for the function. To find an output for a specific value of X, just enter the number into the calculator. For example, if you want to know what the Y value is for an input of 2, enter “2” into your calculator after pressing the “Trace” button.

Tips & Warnings

• Make sure your equation is in the form "Y=" to enter it into your calculator. For example, if your expression is 21 = 5 - x, you'll need to convert to the form y = -16 - x before entering it into the calculator.

References

• "Functions and Change"; Bruce Crauder & Benny Evans; 2007