Which algebraic expression models the given word phrase? 5 times the sum of a and b

1-for what value of x is line a parallel to line b 2-for what value of x is line a parallel to line b

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?

Use composition to determine if (x) or h(x) is the inverse of f(x) for the limited domain x2-1.