Answer:
A and C
Step-by-step explanation:
solving the equations
A
x² - 4 = 0 ( add 4 to both sides )
x² = 4 ( take square root of both sides )
x = ± 
= ± 2 ← required solution
B
x² = - 4 ← has no real solutions
C
4x² = 16 ( divide both sides by 4 )
x² = 4 ( take square root of both sides )
x = ± = ± 2 ← required solution
D
2(x - 2)² = 0 , then
x- 2 = 0 ( add 2 to both sides )
x = 2 ← not the required solution
Answer:
-1/2
Step-by-step explanation:
This is a ratio problem; the ratio of the length to width is constant (and therefore equal):
4 /6 = 15 / x
Now, with a ratio, we may do any allowable algebra operation: cross-multiply, invert both sides, multiply or divide both sides by the same amount, etc.
Let's cross-multiply:
4x = (15)(6)
x = 90/4
x = 22.5 in.
Answer:
34.134%
68.268%
Step-by-step explanation:
Given that:
Mean (m) = 500
Standard deviation (s) = 100
Percentage between 500 and 600
P(500 < x < 600)
P(x < 600) - P(x < 500)
Z = (x - m) / s
P(x < 600)
Z = (600 - 500) /100 = 1
P(x < 500)
Z = (500 - 500) / 500 = 0
P(Z< 1) - P(Z < 0)
0.84134 - 0.5
= 0.34134
= 0.34134 * 100%
= 34.134%
B.) Between 400 and 600
P(x < 400)
Z = (400 - 500) /100 = - 1
P(x < 600)
Z = (600 - 500) / 500 = 1
P(Z< 1 ) - P(Z < - 1)
0.84134 - 0.15866
= 0.68268
= 0.68268 * 100%
= 68.268%
Answer:
2
Step-by-step explanation:
Use order of operations PEMDAS
3^2 = 9 * 2 = 18
20-18= 2
