Answer:
Step-by-step explanation:
See the attached picture:
a simple way to do away with denominators, is we can simply multiply both sides by the LCD, in this case the LCD is 3, so let's multiply both sides by 3.

Do the parentheses first
Since it’s dividing you are supposed to times it
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).