Tanya's parents gave her $500 for her high school graduation. She put the money into a savings account that earned 7.5% annual interest. How much money does she have after 9 months

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.