Please answer i need serious help! (no links please unless they r from true sights) thank you

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?

What set does not contain -3 the set of all real numbers the set of all integers the set of all whole numbers the set of all rational numbers

Express the following as a function of a single angle. cos(60) cos(-20) - sin(60) sin(-20)