Answer:
A sample of 499 is needed.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of 
, and a confidence level of 
, we have the following confidence interval of proportions.
In which
z is the zscore that has a pvalue of 
.
The margin of error is given by:
In this question, we have that:
90% confidence level
So 
, z is the value of Z that has a pvalue of 
, so 
.
How large a sample would be required in order to estimate the fraction of tenth graders reading at or below the eighth grade level at the 90% confidence level with an error of at most 0.03
We need a sample of n, which is found when 
. So
Rounding up
A sample of 499 is needed.
Solve for d:
(3 (a + x))/b = 2 d - 3 c
(3 (a + x))/b = 2 d - 3 c is equivalent to 2 d - 3 c = (3 (a + x))/b:
2 d - 3 c = (3 (a + x))/b
Add 3 c to both sides:
2 d = 3 c + (3 (a + x))/b
Divide both sides by 2:
Answer: d = (3 c)/2 + (3 (a + x))/(2 b)
-----------------------------
Solve for x:
(3 (a + x))/b = 2 d - 3 c
Multiply both sides by b/3:
a + x = (2 b d)/3 - b c
Subtract a from both sides:
Answer: x = (2 b d)/3 + (-a - b c)
____________________________
Solve for b:
(3 (a + x))/b = 2 d - 3 c
Take the reciprocal of both sides:
b/(3 (a + x)) = 1/(2 d - 3 c)
Multiply both sides by 3 (a + x):
Answer: b = (3 (a + x))/(2 d - 3 c)
Hey there!
Okay let's get cracking :D
The equation is.... (2x/3) - 6 = 9
2x/3 = 15
2x = 45
<u>x = 22.5</u><u /> <----- And that is your answer!
I hope it helped!
<u>Please vote for me as Brainliest if there is a second answer!</u>
Answer:
4/2
Step-by-step explanation:
Rise/Run
4/2
With the facts you got here, you can make the following equation:
x*(x+2)=24
x^2+2x=24
x^2+2x-24=0
Then you can use the following formula (which you might have seen before):
x = (-b +/- sqrt(b^2-4ac))/2a
where
ax^2+bx+c=0
(-2 +/- sqrt(4+96))/2
(-2 +/- 10)/2
x_1 = 4
x_2 = -6
