What number would have to be added to complete this square x^2 + 10x +?

I believe 25 has to be added as
(x*5)^2 = x^2 + 10x + 25

Ifound this on google “a skewed (non-symmetric) distribution is a distribution in which there is no such mirror-imaging. a "skewed right" distribution is one in which the tail is on the right side. a "skewed left" distribution is one in which the tail is on the left side. the above histogram is for a distribution that is skewed right.” i hope this you for what your looking for