Answer:
68%
Step-by-step explanation:
The Standard Deviation Rule = Empirical rule formula states that:
68% of data falls within 1 standard deviation from the mean - that means between μ - σ and μ + σ.
95% of data falls within 2 standard deviations from the mean - between μ – 2σ and μ + 2σ.
99.7% of data falls within 3 standard deviations from the mean - between μ - 3σ and μ + 3σ.
From the question,
Step 1
We have to find the number of Standard deviation from the mean. This is represented as x in the formula
μ = Mean = 61
σ = Standard Deviation = 8
For x = 53
μ - xσ
53 = 61 - 8x
8x = 61 - 53
8x = 8
x = 8/8
x = 1
For x = 69
μ + xσ
69 = 61 + 8x
8x = 69 - 61
8x = 8
x = 8/8
x = 1
This falls within 1 standard deviation of the mean where: 68% of data falls within 1 standard deviation from the mean - that means between μ - σ and μ + σ.
Therefore, according to the Standard Deviation Rule, the approximate percentage of daily phone calls numbering between 53 and 69 is 68%
Answer:
4i√5
Step-by-step explanation:

Axis -b/2a=-12/2*3=-2
vertex(-2,-3)
x is 
Step-by-step explanation:
Let us revise some rules of exponents
∵ 
- Factorize 27 and 9
∵ 27 = 3 × 3 × 3
∴ 27 = 3³
∵ 9 = 3 × 3
∴ 9 = 3²
Substitute them in the equation
∴ 
- Use the third rule to simplify each side
∴ 
- Use the fourth rule
∵ The bases of the two sides are equal
∴ Their exponents are equal
∴ 3x - 3 = 6x - 14
- Subtract 6x from both sides
∴ -3x - 3 = -14
- Add 3 to both sides
∴ -3x = -11
Divide both sides by -3
∴ x = 
x is 
Learn more:
You can learn more about equations in brainly.com/question/4934417
#LearnwithBrainly
A² + b² = c²
(√3)² + b² = 5²
3 + b² = 25
b ² = 22
b = √22
hope this helps