I’ve figured out the down payment but I’m confused on the other three questions could anyone help?

Find the solutions for a triangle with a =16, c =12, and b = 63º

[10 points, algebra 2-simplifying complex fractions]according to my answer key the restrictions are -1 and 4. but why not positive 1?

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