Performing the indicated multiplication on the left side gives you:
8x-24=8x-24,
8x=8x
1=1
These expressions are true for any real value of x and thus has infinitely many solutions...
With some simple rearrangement, we can rewrite the numerator as

Then factorizing the difference of squares,
, we end up with

The answer to the question
Answer:
(25.732,30.868)
Step-by-step explanation:
Given that in a random sample of 42 people, the mean body mass index (BMI) was 28.3 and the standard deviation was 6.09.
Since only sample std deviation is known we can use only t distribution
Std error = 

t critical for 99% two tailed 
Margin of error
Confidence interval lower bound = 
Upper bound = 