Answer:
Step-by-step explanation:
Suppose the time required for an auto shop to do a tune-up is normally distributed, we would apply the formula for normal distribution which is expressed as
z = (x - u)/s
Where
x = points scored by students
u = mean time
s = standard deviation
From the information given,
u = 102 minutes
s = 18 minutes
1) We want to find the probability that a tune-up will take more than 2hrs. It is expressed as
P(x > 120 minutes) = 1 - P(x ≤ 120)
For x = 120
z = (120 - 102)/18 = 1
Looking at the normal distribution table, the probability corresponding to the z score is 0.8413
P(x > 120) = 1 - 0.8413 = 0.1587
2) We want to find the probability that a tune-up will take lesser than 66 minutes. It is expressed as
P(x < 66 minutes)
For x = 66
z = (66 - 102)/18 = - 2
Looking at the normal distribution table, the probability corresponding to the z score is 0.02275
P(x < 66 minutes) = 0.02275
Answer:
A on edge
Step-by-step explanation:
i just took the quiz
Answer:
<h2>Cubing both sides of an equation is reversible.</h2>
Step-by-step explanation:
Squaring both sides of an equation is irreversible, because the square power of negative number gives a positive result, but you can't have a negative base with a positive number, given that the square root of a negative number doesn't exist for real numbers.
In case of cubic powers, this action is reversible, because the cubic root of a negative number is also a negative number. For example
![\sqrt[3]{x} =-1](https://tex.z-dn.net/?f=%5Csqrt%5B3%5D%7Bx%7D%20%3D-1)
We cube both sides
![(\sqrt[3]{x} )^{3} =(-1)^{3} \\x=-1](https://tex.z-dn.net/?f=%28%5Csqrt%5B3%5D%7Bx%7D%20%29%5E%7B3%7D%20%3D%28-1%29%5E%7B3%7D%20%5C%5Cx%3D-1)
If we want to reverse the equation to the beginning, we can do it, using a cubic root on each side
![\sqrt[3]{x}=\sqrt[3]{-1} \\\sqrt[3]{x}=-1](https://tex.z-dn.net/?f=%5Csqrt%5B3%5D%7Bx%7D%3D%5Csqrt%5B3%5D%7B-1%7D%20%5C%5C%5Csqrt%5B3%5D%7Bx%7D%3D-1)
There you have it, cubing both sides of an equation is reversible.
Answer:
it's (A) - There are no solutions to the system because the equations represent parallel lines. Just took the quiz.
Step-by-step explanation: