Answer:
x=2
Step-by-step explanation:
add 2x to both sides and subtract 5 from both sides
6x = 12
divide by 6
x=2
Answer: 18
Step-by-step explanation:
The formula to find the minimum sample size is given by :_

, where
= population standard deviation.
z*= critical z-value.
E= Margin of error.
Given : 
E= ± 8
We know that critical value corresponding to 99% confidence level = z*=2.576 [Using z-table]
Then, the required sample size would be :


[Round to next integer.]
Hence, the required minimum sample size = 18
Answer:
18.6
Step-by-step explanation:
area = ( top rule + bottom rule ) × height / 2
area = ( 2 + 3 ) × 4 / 2
area = 5 × 4 / 2
area = 20 / 2
area = 10