What is the slope of the graph shown below

Which expression is not a polynomial?

Express the following as a function of a single angle. cos(60) cos(-20) - sin(60) sin(-20)

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.