Which of the following sets of numbers could represent side lengths of a right triangle?

Researchers were interested in whether relaxation training decreases the number of headaches a person experiences. they randomly assigned 20 participants to a control group or a relaxation training group and noted the change in number of headaches each group reported from the week before training to the week after training. which statistical analysis should be performed to answer the researchers' question?

Ijust need to see how to do this. so you don’t have to answer all of them just a step by step explanation of one.

What is the anwers for 9+2x=5x-3-x