An algebra formula sheet is used to remind you of common algebraic formulas, such as the point-slope form of a line, while you are working through math problems. The best way to use a formula sheet is to write as clearly and concisely as possible and to only include the bare minimum of information necessary to remind you of the formulas and equations that are important for your upcoming exam or assignment.
To determine what information should be on your formula sheet, go through a practice exam or the sections of your text book that are on the exam. Include all of the formulas and equations that are used in the text book example problems, as well as the ones that are required to answer the assigned questions.
Sometimes you are required to memorize the formulas and equations, and other times you can use the sheet during an examination. If you are required to memorize everything, the best way to do so is by doing a lot of problems by hand, making sure to fully write out the formula or equation and the steps it took to reach the solution each time. If you have limited time to study and are allowed to use the formula sheet on your exam, it can be helpful to include examples of solved problems.