Need help on this question. Anything is appreciated:) (8th grade math)

Find the roots of the equation below. x^2 - 6 + 9 = 0

Explain why the factor 1.5 is broke. into two numbers in the model.

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.