If value of cos330° is √3/2 then find tan165°.​

The marriott family bought a new apartment three years ago for $65,000. the apartment is now worth $86,515. assuming a steady rate of growth, what was the yearly rate of appreciation? what is the percent of the yearly rate of appreciation?

Ineed with question three. i don't understand how i'm supposed to achieve 3 marks.

Find the vertex for the parabola given by the function ƒ(x) = −3x2 − 6x.