What set(all) of 3 numbers equal 23

Complete the standard form of the equation that represents the quadratic relationship displayed above, where a, b, and c are rational numbers.

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.

Which of these numbers of simulations of an event would be most likely to produce results that are closest to those predicted by probability theory? 15, 20, 5, 10