When a number is decreased by 28%, the result is 60. What is the original number to the nearest tenth?

83.3

Step-by-step explanation:

When the number is decreased by 28%, we have 72% left (28+72=100%).

28% in decimal form is 0.28

Think of x as the original number.

x - 0.28x = 60

0.72x = 60

x = 83.33

83.33 rounded to the nearest tenth is 83.3

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