K can be 10,11,14,25
Work
(2x+4)(X+3)
(2x+3(X+4)
(2x+6)(X+2)
(2x+2)(X+6)
(2x+1)(X+12)
(2x+12)(X+1)
We can distribute
2(5)+2(-x)=10-2x
we get
8+10-2x=?
18-2x=?
whatever that ? is, we don't know
multiply both sides by -1
2x-18=-?
add 18 to both sides
2x=18-?
divide bth sides by 2
x=9-(?/2)
whatever the left side it, just divide it by 2 and subtract it from 9
The usual margin of error we strive for is a 95% probability that our estimate is within the margin. Assuming a normal distribution (and that we have a big enough sample not to worry about t tests) that corresponds to between minus and plus two standard deviations of the mean (remember the 68-95-99.7 rule). So our margin of error is plus or minus two standard deviations.
Answer: ±2%
10.75
11.50
11.80
12.55
13.30
14.05
14.80
15.55
