Is 0.35 a rational or irrational number

Which graph represents the following piecewise defined function?

Solve the system of equations. y= 2x y= x^2 - 15

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.