Which statement is true about the in triangle PQR?

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.

Click on the graphic until you find the right quotient. (36xa - 30xb) ÷ (-6x2)

Just tell me how to set up the equation.