So when you are doing this u will have to make a sentence
Step two- You will have to combined like terms with x
Step three- You will combine like terms with the regular numbers
step 4- you will then divide x by the number
The sum of all the angle measures is 180 degrees, now lets set up some equations:

Thus x = 22
Hope that helps!
this is as far as i could get. sorry
Answer:
Step-by-step explanation:
Hello!
You have sample of n=7 with mean X[bar]= 1403 and standard deviation S=27 and are required to estimate the mean with a 95%CI.
Asuming this sample comes from a normal population I'll use a stuent t to estimate the interval (a sample of 7 units is too small for the standard normal to be accurate for the estimation):
[X[bar]±
*
]

[1403±2.365*
]
[1378.87;1427.13]
The margin of error is the semiamplitude of the interval and you can calculate it as:

With a confidence level of 95% you'd expect that the real value of the mean is contained by the interval [1378.87;1427.13], the best estimate of the mean value is expected to be ± 24.13 of 1403.
I hope it helps!