Three friends go bowling at "Strike Out" on Friday night. The cost per person per game is $5.30. The cost to rent shoes is $2.50 per person. Their total cost is $55.20. How many games of bowling did the friends play?

They played 3 games of bowling.

Step-by-step explanation:

Assuming each person only rents one pair of shoes, that would come out to $7.50.

Subtract this amount from the total ($55.20) and you get $47.70 leftover.

Divide the leftover amount by the price of games per person ($5.30) and you'll get nine, divide that by the number of people playing, since it's per person, and you can determine they played three games.

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