Idon't know how to do this it is hard

What is the inverse of the function f(x)=2x+1

Change negative exponents to positive. then solve. round to four decimal places

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?