Geometry ? ? can someone me with questions 15, 16, 17, and 18?

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.

Is there an x intercept in the equation 60*1.15^x

The ratios of boys to girls on a soccer league is 2: 5. if there are 28 boys, how many girls are playing soccer? extra points! will mark as brainiest asap