123 x 23 standard algorithm

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.

1-for what value of x is line a parallel to line b 2-for what value of x is line a parallel to line b

[15 points, algebra 2]simplify the complex fraction and find the restrictions.