Imani used the equation 8/2+b/2=17/2 to find the distance from the top of the balloon to the ground in the example why does equation also work

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.

F. a fair coin is thrown in the air four times. if the coin lands with the head up on the first three tosses, what is the probability that the coin will land with the head up on the fourth toss? a. 0 b. 1/16 c. 1/8 d. 1/2

Abag contains 5 red marbles , 6 blue marbles and 4 green marbles. susie selects a marble and returns it to the bag before selecting another marble. if susie selects a red marble 6 out of 20 times, what is the experimental probability that the next marble she selects will be a red marble ?