How do u work 9n=5? just write it the way u worked it

Brent wants to know what is 5 x 1/2

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 best explains why this triangle is or is not a right triangle?