Two numbers total 26 and have a difference of 6. find the two numbers

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?

Which compound inequality could be represented by the graph?

Ineed i been stuck on this question since yesterday