Are all of these four right ? if not, plz

The data represents the semester exam scores of 8 students in a math course. {51,91,46,30,36,50,73,80} what is the five-number summary?

At a kentucky friend chicken, a survey showed 2/3 of all people preferred skinless chicken over the regular chicken. if 2,400 people responded to the survey, how many people preferred regular chicken?

Prove (a) cosh2(x) − sinh2(x) = 1 and (b) 1 − tanh 2(x) = sech 2(x). solution (a) cosh2(x) − sinh2(x) = ex + e−x 2 2 − 2 = e2x + 2 + e−2x 4 − = 4 = . (b) we start with the identity proved in part (a): cosh2(x) − sinh2(x) = 1. if we divide both sides by cosh2(x), we get 1 − sinh2(x) cosh2(x) = 1 or 1 − tanh 2(x) = .