You just signed a contract for a new job. the salary for the first year is $30,000 and there is to be a percent increase in your salary each year. the algebraic expression to the right describes your total salary over n years, where x is the sum of 1 and the yearly percent increase, expressed as a decimal.

Sounds like a geometric progression.  Initial value is $30,000; p is the annual increase, a percent, but expressed as a decimal fraction between 0 and 1; n is the number of years.

Total salary = $30,000 (1+p)^n, or, in shorthand and following the wording of this problem,

Total salary = $30,000 x^n, where x = 1 + p