Question

A theater can seat 725 people. The number of rows is 4 less than the number of seats in each row. How many rows of seats are there?

Answer 1

725 is equal to (number of rows)*(number of seats per row)
r = s-4
725 = (s-4)s
s^2-4s-725 = 0
Factoring: (s-29)(s+25) = 0
Thus there are 29 seats per row, and 25 rows.