Answer :
320 = 2x² - 12x as when there are an unknown number of rows there are 320 seats.
0 = 2x² - 12x - 320
0 = x² - 6x - 160
0 = (x - 16)(x + 10)
for this to = 0 one bracket must equal 0
therefore x = 16 or x = -10
not a negative number of rows.
Therefore must be 16.
0 = 2x² - 12x - 320
0 = x² - 6x - 160
0 = (x - 16)(x + 10)
for this to = 0 one bracket must equal 0
therefore x = 16 or x = -10
not a negative number of rows.
Therefore must be 16.