Just 2 Questions, I'm lost about everything :|

Which of the expressions (on the photo document i inserted) together represent all solutions to the following equation? 8cos(12x)+4=-4 *the answer should be in degrees.* > i would like for someone to explain the process to find the solutions for this.

Place the following steps in order to complete the square and solve the quadratic equation,

Angles r and s are complementary. the measure of angle r is 31 degrees. which equation can be used to find angle s?