PLSSS HELP IF YOU TURLY KNOW THISS

If x + 10 = 70, what is x? a. 40 b. 50 c. 60 d. 70 e. 80

What is the best way to answer questions with a x expression in the question. for example 3x + 10x=?

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.