How do you answer number 4 & number 6 ? ‍♀️ explain ! ?

What are the solutions of the system? solve by graphing. y = -x^2 -6x - 7 y = 2

In a singing competition, there are 150 participants. at the end of each round, 40% of the participants are eliminated. how many participants are left after n rounds?

What is the distance from zero if a quadratic function has a line of symmetry at x=-3 and a zero at 4