15. (no calculator) a restaurant took 1/3 of an hour to use 1/5 of a
package of napkins. at this rate, how many hours would it take to use the
entire package?

It would take 5/3 or 1 2/3 hours to use a package of napkins.

Step-by-step explanation:

1/3=1/5

2/3=2/5

3/3=3/5

4/3=4/5

5/3=5/5

5/3= 1 2/3

whats the

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