The width of a rectangle is 2x²+9x-7 and the length is x²-9. Find the perimeter of the rectangle.​

Ametal rod is 2/5 meters long. it will be cut into pieces that are each 1/30 meters long. how many pieces will be made from the rod?

Find the rate at which the water is now flowing from the tap give your answer cubic centimetres per second

Researchers are conducting experiments to determine the role of alcohol in the development of depression. after the study is complete, they determine that the relative risk of developing depression is 1.55 with a 95 % ci of 1.2 -1.9. each group is then divided into nonsmokers and smokers. the relative risk for the nonsmokers is 1.12 with a 95% ci of 0.87-1.37. the relative risk for the smokers is 1.7 with a 95 % cl of 1.5-1.9. what type of bias may affect this study? a. procedure bias b. recall bias c. selection bias d. confounding e. lead-time bias