Please help? what does x equal?

Arectangular exercise mat has a perimeter of 36 feet the length of the mat is twich the width writeand solve an equation to determine the length in feet. of the mat then find the area in square feet of the mart

How do i do this activity, is appreciated

Atextile fiber manufacturer is investigating a new drapery yarn, which the company claims has a mean thread elongation of 12 kilograms with a standard deviation of 0.5 kilograms. the company wishes to test the hypothesis upper h subscript 0 baseline colon mu equals 12 against upper h subscript 1 baseline colon mu less-than 12 using a random sample of n equals 4 specimens. calculate the p-value if the observed statistic is x overbar equals 11.8. round your final answer to five decimal places (e.g. 98.76543).