Geometry math question no guessing and show work

Which of the following is true for the relation f(x)=2x^2+1

If the value of cos330°is√3/2 then find cos 165°.

The human resources manager at a company records the length, in hours, of one shift at work, x. he creates the probability distribution below. what is the probability that a worker chosen at random works at least 8 hours? 0.62 0.78 0.84 0.96