Answer:
18x^2+6
Step-by-step explanation:
2(9x^2+3)
multiply each term in parentheses by 2
2 x 9x^2+2 x 3
calculate product
18x^2+2 x 3
multiply numbers
18x^2+6
If you want to solve for x you have to get x alone on one side of the equals sign. In order to do that you have to get rid of the stuff on the same side by doing the opposite operation so that it cancels. What you do on one side you do on. the other side to keep the equation true.
y= abx
a and b are being multiplied by x so divide by ab to cancel them out (ab/ab is 1).
y= abx/ab (ab cancels)
now divide the other side by ab to keep the equation true.
y/ab= x
The question is incomplete! Complete question along with answer and step by step explanation is provided below.
Question:
The lifetime (in hours) of a 60-watt light bulb is a random variable that has a Normal distribution with σ = 30 hours. A random sample of 25 bulbs put on test produced a sample mean lifetime of = 1038 hours.
If in the study of the lifetime of 60-watt light bulbs it was desired to have a margin of error no larger than 6 hours with 99% confidence, how many randomly selected 60-watt light bulbs should be tested to achieve this result?
Given Information:
standard deviation = σ = 30 hours
confidence level = 99%
Margin of error = 6 hours
Required Information:
sample size = n = ?
Answer:
sample size = n ≈ 165
Step-by-step explanation:
We know that margin of error is given by
Margin of error = z*(σ/√n)
Where z is the corresponding confidence level score, σ is the standard deviation and n is the sample size
√n = z*σ/Margin of error
squaring both sides
n = (z*σ/Margin of error)²
For 99% confidence level the z-score is 2.576
n = (2.576*30/6)²
n = 164.73
since number of bulbs cannot be in fraction so rounding off yields
n ≈ 165
Therefore, a sample size of 165 bulbs is needed to ensure a margin of error not greater than 6 hours.
Answer:
she spends 300 minutes in art class a week
Step-by-step explanation:
5 x 60 is 300
