1. The mean of the data set{9,5,y,2,x} is twice the data set {8,x,4,1,3}. What is (y-x) squared. 2. How many alcohol must be added to480 grams of hand sanitizer that is 24% alcohol to make it a hand sanitizer that is 40% alcohol?

1. (y - x)²  = 256

2. 128g needed to be added

Step-by-step explanation:

1.

9 + 5 + 2 + y + x = 2(8 + 4 + 1 + 3 + x)

16 + y + x = 32 + 2x

y - x = 16

∴ (y - x)²  = 256

2.

x = mass of alcohol to add

480 × 0.24 = 115.2 ← current mass of alcohol

0.4(480 + x) = 115.2 + x      (×5)

2(480 + x) = 576 + 5x

960 + 2x = 576 + 5x

3x = 384

x = 128g

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