Find the length of x

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?

The revenue each season from tickets at the theme park is represented by t(c)=5x. the cost to pay the employees each season is represented by r(x)=(1.5)^x. examine the graph of the combined function for total profit and estimate the profit after four seasons

2x minus y equals 6, x plus y equals negative 3