Ireally need with this i have no clue what im doing !

f(x)=9x^3+2x^2-5x+4 and g(x)=5x^3-7x+4. what is f(x)-g(x)? show all of your steps and write your final answer in factored form

1. according to the internal revenue service, the mean tax refund for the year 2007 was $2,708. assume the standard deviation is $650 and that the amounts refunded follow a normal probability distribution. a. what percent of the refunds are more than $3,000? b. what percent of the refunds are more than $3,000 but less than $4,000? c. what percent of the refunds are less than $2,000?