Answer:
The 95% confidence interval for the percent of all black adults who would welcome a white person into their families is (0.8222, 0.8978).
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
.
For this problem, we have that:
323 blacks, 86% of blacks said that they would welcome a white person into their families. This means that 
95% confidence level
So
, z is the value of Z that has a pvalue of
, so
.
The lower limit of this interval is:

The upper limit of this interval is:

The 95% confidence interval for the percent of all black adults who would welcome a white person into their families is (0.8222, 0.8978).
The value of x is √8/3 - 2
Step by step explanation:
The given equation is
3(x+2)^2=8
To find x,
(x+2)²= 8/3
By taking square root on both sides
x+2= √8/3
x=√8/3 -2
x= -0.37
Thus the square root for the given value is -0.37
Step-by-step explanation:
1 10.38
2 16.77
3 11.499
4 11.486
5 0.0947
6 30.52875
7 525
8 32.57862069
9 16.5625