What is the difference between correlation and dependencies?

Dependency: A variable whose value depends on the value assigned to another variable (independent variable).

Correlation: The relationship between two or more variables is considered as correlation. 

 In statistics, when we talk about dependency, we are referring to any statistical relationship between two random variables or two sets of data. Correlation, on the other hand refers to any of a broad class of statistical relationships involving dependence. 

none of the above.

for one of the equations to be used in the process, there has to be a term in the equation since squared is .

since there is only a term in the first equation, we cannot derive a from completing the square.

solving with completing the square

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