Do 1,2,3,4 For 30 points

Is a positive integer raised to a negative power always positive

Okay so i didn't get this problem petro bought 8 tickets to a basketball game he paid a total of $200 write an equation to determine whether each ticket cost $26 or $28 so i didn't get this question so yeahyou have a good day.

Idon't get undoing if its pass adding and subtracting so can someone ? x-2 over 5 = 18