82 I think that’s the answer because that’s my opinion if it’s wrong I don’t know what to tell you
Answer:
Step-by-step explanation:
We want to determine a 95% confidence interval for the population mean.
Number of sample, n = 56
Mean, u = 645 hours
Standard deviation, s = 31 hours
For a confidence level of 95%, the corresponding z value is 1.96.
We will apply the formula
Confidence interval
= mean ± z ×standard deviation/√n
It becomes
645 ± 1.96 × 31/√56
= 645 ± 1.96 × 4.142
= 645 ± 8.12
The lower end of the confidence interval is 645 - 8.12 =636.88
The upper end of the confidence interval is 645 + 8.12 =653.12
Therefore, with 95% confidence interval for the population mean life of fluorescent light bulbs is between 636.88 hours and 653.12 hours
2(2ax-y)=3ax-4y
4ax-2y=3ax-4y
Move 3ax from the right to the left. You do so by subtracting 3ax from both sides. Once doing so, you should have:
ax-2y=-4y
Isolate ax. You do so by adding (-2y) to both sides. After doing so, you should have:
ax=-2y
To isolate y by itself, you divide everything by -2, thus, equaling y= ax/-2
