HELP PLEASE this is due tomorrow for me!!

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.

On #16 : explain how factoring a trinomial, ax^2+ bx+ c, when a does not equal 1 different from factoring a trinomial when a = 1.

Out of 50 students surveyed, 16 have a dog. based on these results, predict how many of the 280 students in the school have a dog.