Answer:
4x2–12x+33=0
Resta 4x
2
en los dos lados. Cualquier valor restado de cero da como resultado su valor negativo.
−12x+33=−4x
2
Resta 33 en los dos lados.
−12x=−4x
2
−33
Divide los dos lados por −12.
−12
−12x
=
−12
−4x
2
−33
Al dividir por −12, se deshace la multiplicación por −12.
x=
−12
−4x
2
−33
Divide −4x
2
−33 por −12.
x=
3
x
2
+
4
11
Resolver para x_2
x
2
=3x−
4
33
Step-by-step explanation:
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.
4-x=3
Double the 3 witch is =6
And add 8 witch is
6+8=14