Can somebody help me please? I managed to get 2 marks but I don't know what i did wrong

What is the first step of an indirect proof of a number that is divisible by two

Simplify. (-2)^-3 a. -8 b. -1/8 c. 1/8 d. 8

Raymond just got done jumping at super bounce trampoline center. the total cost of his session was $43.25 . he had to pay a $7 entrance fee and $1.25 for every minute he was on the trampoline. write an equation to determine the number of minutes (t) that raymond was on the trampoline.