These endpoints are called the vertices. Why cant you square both sides of an equation. GMAT Problem Solving questions ask you to use your mathematical problem-solving skills to find the correct answer to a math problem while Data Sufficiency questions ask you to analyze mathematical data presented in order to determine whether you have enough information to solve a problem or what information is necessary to do so.
This quadratic happens to factor.
One equation is a constraint equation and the other is the optimization equation. A great indication that you can plug in the answer. For example if you want to memorize the math formula for a quadratic equation then you could write the formula on 1 side of the card and then write an explanation of how to use the formula along with an example on the opposite side. The correct answer could either be 40 or 96.