Which operations can be applied to a matrix in the process of gauss-jordan elimination? replacing a row with twice that row replacing a row with the sum of that row and another row replacing a row with three times another row swapping rows replacing a row with the absolute values of that row

Data was collected on myrtle beach for 11 consecutive days. each day the temperature and number of visitors was noted. the scatter plot below represents this data. how many people visited the beach when the temperature was 84 degrees?

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?

What can you determine about the solutions of this system