Pls help me with this question

Anyone know? is appreciated! will mark brainliest if correct!

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.

Given the two similar triangles, how do i find the missing length? if a=4, b=5, and b'=7.5 find a'