Looking for any of the first 5 questions answered if multiple can be answered thats even better

The school that imani goes to is selling tickets to the annual dance competition. on the first day of the ticket sales the school sold 7 adult tickets and 5 child tickets for a total of $96. the school took in $40 on the second day by seling 3 adult tickets . find the price of an adult ticket and the price of a child ticket. solve by using substitution elimination college prep algebra math heres the 2 equations i came up with 7x+5y=96 and 3x+2y= -40 show all workiv be stuck on this.

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?

Simplify using positive exponents only.