A threaten can seat 391 people. The number of rows is 6 less than the number of seats in each row. How many rows of seats are there

Question

How many rows of seara are there 

Answer 1

r*(r-6) = 391

 

r^2 - 6r - 391 = 0

 

( R     -    23 )( R    +      17  ) = 0

 

R = 23 or R = -17 <-- reject

 

There are 23 rows with 17 seats in each row