Press the "ON" key. Press the "Home" key to get to the TI-89 home page. Press the "F2" key to bring up the algebra menu. Refer to the web page titled "Texas Instruments: Module_13" listed in the resource section below to help you find the "F2" key and others on the keyboard. There are 11 different choices on the algebra menu, which include solve, factor, expand and zeros.
Select expand -- choice 3 on the algebra menu -- to expand an algebraic function. "Expand" appears on the command line. Expand the function, x + 1 quantity squared or, in math symbolics, (x+1)^2 for this example. Enter this algebra expression using your keyboard keys so that the command on the command line will be: expand ((x+1)^2). The expand function will work only if it is completely contained within parentheses. Press "Enter." The screen will display: x^2 + 2x + 1. This is the expanded form of the equation.
Press the "F2" key again. Select factor, which is choice 2. Use the expanded algebraic expression from Step 2. Enter the equation x^2 + 2x + 1 into the command line. Check that the syntax of the final command reads: factor(x^2+2x+1). The factor command also requires that the algebraic expression be enclosed by parentheses. Press "Enter." The algebraic expression entered in Step 2, (x+1)^2, is displayed. This is the factored form of the equation.
Press the "F2" key again. Select choice 4, zeros. Enter the same algebraic expression as you did in Step 3: x^2 + 2x + 1. Append a comma after the expression, enter x and then enter a closing parenthesis. The expression must be within parentheses. Check the syntax and ensure that it reads zeros(x^2 + 2x +1, x). Press "Enter" key. The display lists -1 (negative one) as the zero. Substitute -1 for x in the algebraic expression and check that the value of the algebraic expression is equal to 0, as the definition of a zero requires.