How can a quadratic function be analyzed to identify and interpret key features?

Why do interests rates on loans to be lower in a weak economy than in a strong one

Which of the following tables represents exponential functions?

Is the product of two rational numbers irrational or rational? first, make a hypothesis by multiplying two rational numbers. then, use variables such as x=a/b and y=c/d and the closure property of integers to prove your hypothesis.