Of the 140 7th graders, 15% earn the Presidential Physical Fitness award. How many students earn the award? *

21 students

Step-by-step explanation:

the percent proportion is a/w = p/100

where A is a part of the whole W, and p% or p/100 is the percent

a/140 = 15/100 (Substitute w =140 and p= 15)

a times 100=140 times 15 (cross poducts property)

100a=2100  (Multiply)

100a/100 = 2100/100 (divide both sides by 100)

a = 21 (simplify)

So, 21 students win the award.

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