Whats the proper abbreviation for twenty-five micrograms

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

Which statements describe the solutions to the inequality x< -20 check all that apply. there are infinite solutions. each solution is negative. each solution is positive. the solutions are both positive and negative. the solutions contain only integer values. the solutions contain rational number values.

Use the given information to determine the exact trigonometric value.