Help me pls T^T this is due today

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.

Prove that the value of the expression 7^8–7^7+7^6 is divisible by 43.

Which equation is y = -6x2 + 3x + 2 rewritten in vertex form?