How would one derive computational formula for standard deviation from definition using elementary algebra?

Question

dumbcow · Answer

how do you mean
$$s = \sqrt{\frac{\sum_{}^{}(x _{i}-X)^{2}}{n-1}}$$

anonymous · Answer

This is an extra credit question and this is literally all the information the teacher gave us.

dumbcow · Answer

its the square root of the average squared deviation

anonymous · Answer

so thats the answer?

anonymous · Answer

What definition were you given in your class?

anonymous · Answer

$$s= \sqrt{n \Sigma(x^{2}}) - (\Sigma x)^{2} / n(n-1)$$well he didn't teach us computational standard deviation and its not in the book so i looked it up and it's suppose to look like this and the n(n-1) is under the equation but in the square