Someone help me pls. 24 points

Ineed with number 17 i don’t get it at alll

12. the amount of money in a bank account decreased by 21.5% over the last year. if the amount of money at the beginning of the year is represented by ‘n', write 3 equivalent expressions to represent the amount of money in the bank account after the decrease?

Which statements regarding efg are true? check all that apply.