First of all, RELAX.
This is an “assessment,” NOT A TEST. The difference is that an assessment is designed to determine what you know. At the end of the ALEKS Placement Assessment, you will have a much better sense of your strengths and weaknesses in math. You will then have a chance to work on those weaknesses. There is really no penalty for incorrectly answering a question on the assessment. The most important thing is that you take the assessment seriously and give it an honest effort so that the assessment truly reflects your level of knowledge and math preparedness.
Be honest about your skill level.
There is no benefit to cheating on the placement assessment – your only reward will be that you are forced to take a class that is too difficult for your current level of mathematical knowledge. Therefore, while you are taking the assessment, do not consult any other source for help (friends, family, internet searches, etc.). The purpose of the placement assessment is to give an accurate measure of your current mathematical skills so that you will be successful in your mathematics courses.