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.
Multiply both by -1: 113.75-112=1.75
multiply answer by -1: -1.75
A submarine descends below the oceans surface at a rate of 75 feet per minute. How naby feet below the iceabs surface will the submarine be in 12 minutes
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The answer is A.
(a-1)(a-2)
a * a= a^2
a * -2= -2a
a * -1 = -1a = a
-1 * -2 = 2 because two negative signs make a positive.
Put them together:
a^2 - 2a - a + 2
= a^2 - 3a +2
The given in the problem above is an arithmetic sequence with the first term equal to 4 and the common difference is 5. To determine the number of seats on row 23, use the formula,
an = a1 + (n - 1) d
Solving for the 23rd term,
an = 4 + (22) 5 = 114 seats
Therefore, the answer is there are 114 seats on the 23rd row.
