An auditorium has 15 rows of seats. Each row except the first has the same number of seats. The first row has 12 seats. On one occasion, 230 people were seated in the auditorium, and there were still empty seats. On another occasion, 240 people came to the auditorium, but there were not enough seats for all of them. How many seats are in the auditorium?

x = ±sqrt(10)

step-by-step explanation:

5 - 2x² = -15

subtract 5 from each side

5-5 - 2x² = -15-5

-2x^2   = -20

divide by -2 on each side

-2x^2   /-2= -20/-2

x^2 =10

take the square root on each side

sqrt(x^2 )=±sqrt(10)

x = ±sqrt(10)

check:

5 - 2x² = -15

+sqrt(10)

5 - 2(sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

-sqrt(10)

5 - 2(-sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

the answer is 62.8 cubic units

$54.99

step-by-step explanation:

$54.99 includes 500 min. if she does not exceed 500 min then her bill is $54.99

0.50 , 0.75

step-by-step explanation: