How to Program the Quadratic Equation Into a Graphing Calculator
Algebra students will inevitably come across the Quadratic Equation and need to know how to use it to solve complex math problems. There is a program available for graphing calculators that will allow you to type in the A,B, and C values for the problem and get an answer, however this type of program may not be allowed to be used on tests, so you will also need to memorize the formula. This program is for a TI83 graphing calculator, so you may need to change some items to tailor the program to your calculator.
Things You'll Need
 A Graphing Calculator
How to Program the Quadratic Equation Into a Graphing Calculator

Create a new program on your calculator. This is done by pushing the "PRGM" button on your calculator, then scrolling over to "New." Hit "Enter" to create a new program. Title the program "QUADFORM."

Press "PRGM" then scroll to "I/O" and press 3 to get "DISP." Then press "2nd" "Alpha" to Alpha Lock your calculator and type "ENTER A" (make sure you include the quotation marks on each side of ENTER A).

Press "PRGM" then scroll to "I/O" and press 1 to get "Input." Then press "Alpha" and "Math" to get the letter A to appear. You do not need quotation marks around the A in this case.

Repeat steps 2 and 3 two more times, replacing A with B and then with C so the next four lines in the calculator program read: Disp "ENTER B", Input B, Disp "ENTER C", Input C.

Type in the square root followed by B^24AC)>D. The square root will automatically open parenthesis for you, so you will need to close them after the C. The B^2 can be input as B^2 or as B squared. The > sign is found above the "ON" button where it says "STO>".

Press in the following: (B)/(2A)>I. Where the  before the B is the negative sign, NOT the minus sign.

Type in the following on the next line: (D)/(2A)>F Then type in the following on the line after that: (D)/(2A)>S

Press "PRGM" then scroll over to "I/O" and press 3 for "Disp." Then type in I+F, I+S. This will give you the results of the quadratic formula when you use the program.
Tips & Warnings
 Memorize the Quadratic Formula for tests and quizzes where you can not use your calculator.
 Change the above program to fit your specific calculator.
 Don't program formulas into your calculator unless it is oked by your professor.
 Make sure you know how to use a formula without the program, in case calculators are not allowed on tests.
Resources
 Photo Credit http://www.sxc.hu/photo/908799